diff options
Diffstat (limited to 'kernel')
55 files changed, 1634 insertions, 1253 deletions
diff --git a/kernel/Makefile b/kernel/Makefile index 6c57e78817da..62471e75a2b0 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -30,6 +30,7 @@ KCOV_INSTRUMENT_extable.o := n # Don't self-instrument. KCOV_INSTRUMENT_kcov.o := n KASAN_SANITIZE_kcov.o := n +CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) # cond_syscall is currently not LTO compatible CFLAGS_sys_ni.o = $(DISABLE_LTO) diff --git a/kernel/backtracetest.c b/kernel/backtracetest.c index 1323360d90e3..a563c8fdad0d 100644 --- a/kernel/backtracetest.c +++ b/kernel/backtracetest.c @@ -48,19 +48,14 @@ static void backtrace_test_irq(void) #ifdef CONFIG_STACKTRACE static void backtrace_test_saved(void) { - struct stack_trace trace; unsigned long entries[8]; + unsigned int nr_entries; pr_info("Testing a saved backtrace.\n"); pr_info("The following trace is a kernel self test and not a bug!\n"); - trace.nr_entries = 0; - trace.max_entries = ARRAY_SIZE(entries); - trace.entries = entries; - trace.skip = 0; - - save_stack_trace(&trace); - print_stack_trace(&trace, 0); + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); + stack_trace_print(entries, nr_entries, 0); } #else static void backtrace_test_saved(void) diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 8974b3755670..3c18260403dd 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -162,10 +162,14 @@ static void cpu_map_kthread_stop(struct work_struct *work) static struct sk_buff *cpu_map_build_skb(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf) { + unsigned int hard_start_headroom; unsigned int frame_size; void *pkt_data_start; struct sk_buff *skb; + /* Part of headroom was reserved to xdpf */ + hard_start_headroom = sizeof(struct xdp_frame) + xdpf->headroom; + /* build_skb need to place skb_shared_info after SKB end, and * also want to know the memory "truesize". Thus, need to * know the memory frame size backing xdp_buff. @@ -183,15 +187,15 @@ static struct sk_buff *cpu_map_build_skb(struct bpf_cpu_map_entry *rcpu, * is not at a fixed memory location, with mixed length * packets, which is bad for cache-line hotness. */ - frame_size = SKB_DATA_ALIGN(xdpf->len + xdpf->headroom) + + frame_size = SKB_DATA_ALIGN(xdpf->len + hard_start_headroom) + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); - pkt_data_start = xdpf->data - xdpf->headroom; + pkt_data_start = xdpf->data - hard_start_headroom; skb = build_skb(pkt_data_start, frame_size); if (!skb) return NULL; - skb_reserve(skb, xdpf->headroom); + skb_reserve(skb, hard_start_headroom); __skb_put(skb, xdpf->len); if (xdpf->metasize) skb_metadata_set(skb, xdpf->metasize); @@ -205,6 +209,9 @@ static struct sk_buff *cpu_map_build_skb(struct bpf_cpu_map_entry *rcpu, * - RX ring dev queue index (skb_record_rx_queue) */ + /* Allow SKB to reuse area used by xdp_frame */ + xdp_scrub_frame(xdpf); + return skb; } diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 2ada5e21dfa6..4a8f390a2b82 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -554,19 +554,6 @@ struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type typ } EXPORT_SYMBOL(bpf_prog_get_type_path); -static void bpf_evict_inode(struct inode *inode) -{ - enum bpf_type type; - - truncate_inode_pages_final(&inode->i_data); - clear_inode(inode); - - if (S_ISLNK(inode->i_mode)) - kfree(inode->i_link); - if (!bpf_inode_type(inode, &type)) - bpf_any_put(inode->i_private, type); -} - /* * Display the mount options in /proc/mounts. */ @@ -579,11 +566,28 @@ static int bpf_show_options(struct seq_file *m, struct dentry *root) return 0; } +static void bpf_destroy_inode_deferred(struct rcu_head *head) +{ + struct inode *inode = container_of(head, struct inode, i_rcu); + enum bpf_type type; + + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_link); + if (!bpf_inode_type(inode, &type)) + bpf_any_put(inode->i_private, type); + free_inode_nonrcu(inode); +} + +static void bpf_destroy_inode(struct inode *inode) +{ + call_rcu(&inode->i_rcu, bpf_destroy_inode_deferred); +} + static const struct super_operations bpf_super_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, .show_options = bpf_show_options, - .evict_inode = bpf_evict_inode, + .destroy_inode = bpf_destroy_inode, }; enum { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index fd502c1f71eb..09d5d972c9ff 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1897,8 +1897,9 @@ continue_func: } frame++; if (frame >= MAX_CALL_FRAMES) { - WARN_ONCE(1, "verifier bug. Call stack is too deep\n"); - return -EFAULT; + verbose(env, "the call stack of %d frames is too deep !\n", + frame); + return -E2BIG; } goto process_func; } @@ -4137,15 +4138,35 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) return 0; } +static void __find_good_pkt_pointers(struct bpf_func_state *state, + struct bpf_reg_state *dst_reg, + enum bpf_reg_type type, u16 new_range) +{ + struct bpf_reg_state *reg; + int i; + + for (i = 0; i < MAX_BPF_REG; i++) { + reg = &state->regs[i]; + if (reg->type == type && reg->id == dst_reg->id) + /* keep the maximum range already checked */ + reg->range = max(reg->range, new_range); + } + + bpf_for_each_spilled_reg(i, state, reg) { + if (!reg) + continue; + if (reg->type == type && reg->id == dst_reg->id) + reg->range = max(reg->range, new_range); + } +} + static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, struct bpf_reg_state *dst_reg, enum bpf_reg_type type, bool range_right_open) { - struct bpf_func_state *state = vstate->frame[vstate->curframe]; - struct bpf_reg_state *regs = state->regs, *reg; u16 new_range; - int i, j; + int i; if (dst_reg->off < 0 || (dst_reg->off == 0 && range_right_open)) @@ -4210,20 +4231,9 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, * the range won't allow anything. * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16. */ - for (i = 0; i < MAX_BPF_REG; i++) - if (regs[i].type == type && regs[i].id == dst_reg->id) - /* keep the maximum range already checked */ - regs[i].range = max(regs[i].range, new_range); - - for (j = 0; j <= vstate->curframe; j++) { - state = vstate->frame[j]; - bpf_for_each_spilled_reg(i, state, reg) { - if (!reg) - continue; - if (reg->type == type && reg->id == dst_reg->id) - reg->range = max(reg->range, new_range); - } - } + for (i = 0; i <= vstate->curframe; i++) + __find_good_pkt_pointers(vstate->frame[i], dst_reg, type, + new_range); } /* compute branch direction of the expression "if (reg opcode val) goto target;" @@ -4697,6 +4707,22 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state, } } +static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id, + bool is_null) +{ + struct bpf_reg_state *reg; + int i; + + for (i = 0; i < MAX_BPF_REG; i++) + mark_ptr_or_null_reg(state, &state->regs[i], id, is_null); + + bpf_for_each_spilled_reg(i, state, reg) { + if (!reg) + continue; + mark_ptr_or_null_reg(state, reg, id, is_null); + } +} + /* The logic is similar to find_good_pkt_pointers(), both could eventually * be folded together at some point. */ @@ -4704,10 +4730,10 @@ static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno, bool is_null) { struct bpf_func_state *state = vstate->frame[vstate->curframe]; - struct bpf_reg_state *reg, *regs = state->regs; + struct bpf_reg_state *regs = state->regs; u32 ref_obj_id = regs[regno].ref_obj_id; u32 id = regs[regno].id; - int i, j; + int i; if (ref_obj_id && ref_obj_id == id && is_null) /* regs[regno] is in the " == NULL" branch. @@ -4716,17 +4742,8 @@ static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno, */ WARN_ON_ONCE(release_reference_state(state, id)); - for (i = 0; i < MAX_BPF_REG; i++) - mark_ptr_or_null_reg(state, ®s[i], id, is_null); - - for (j = 0; j <= vstate->curframe; j++) { - state = vstate->frame[j]; - bpf_for_each_spilled_reg(i, state, reg) { - if (!reg) - continue; - mark_ptr_or_null_reg(state, reg, id, is_null); - } - } + for (i = 0; i <= vstate->curframe; i++) + __mark_ptr_or_null_regs(vstate->frame[i], id, is_null); } static bool try_match_pkt_pointers(const struct bpf_insn *insn, diff --git a/kernel/cpu.c b/kernel/cpu.c index 025f419d16f6..43e741e88691 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -564,6 +564,20 @@ static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); } +static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) +{ + if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) + return true; + /* + * When CPU hotplug is disabled, then taking the CPU down is not + * possible because takedown_cpu() and the architecture and + * subsystem specific mechanisms are not available. So the CPU + * which would be completely unplugged again needs to stay around + * in the current state. + */ + return st->state <= CPUHP_BRINGUP_CPU; +} + static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, enum cpuhp_state target) { @@ -574,8 +588,10 @@ static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, st->state++; ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); if (ret) { - st->target = prev_state; - undo_cpu_up(cpu, st); + if (can_rollback_cpu(st)) { + st->target = prev_state; + undo_cpu_up(cpu, st); + } break; } } @@ -2288,3 +2304,18 @@ void __init boot_cpu_hotplug_init(void) #endif this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); } + +enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO; + +static int __init mitigations_parse_cmdline(char *arg) +{ + if (!strcmp(arg, "off")) + cpu_mitigations = CPU_MITIGATIONS_OFF; + else if (!strcmp(arg, "auto")) + cpu_mitigations = CPU_MITIGATIONS_AUTO; + else if (!strcmp(arg, "auto,nosmt")) + cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; + + return 0; +} +early_param("mitigations", mitigations_parse_cmdline); diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index 45d51e8e26f6..badd77670d00 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -89,8 +89,8 @@ struct dma_debug_entry { int sg_mapped_ents; enum map_err_types map_err_type; #ifdef CONFIG_STACKTRACE - struct stack_trace stacktrace; - unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES]; + unsigned int stack_len; + unsigned long stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES]; #endif }; @@ -174,7 +174,7 @@ static inline void dump_entry_trace(struct dma_debug_entry *entry) #ifdef CONFIG_STACKTRACE if (entry) { pr_warning("Mapped at:\n"); - print_stack_trace(&entry->stacktrace, 0); + stack_trace_print(entry->stack_entries, entry->stack_len, 0); } #endif } @@ -704,12 +704,10 @@ static struct dma_debug_entry *dma_entry_alloc(void) spin_unlock_irqrestore(&free_entries_lock, flags); #ifdef CONFIG_STACKTRACE - entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES; - entry->stacktrace.entries = entry->st_entries; - entry->stacktrace.skip = 2; - save_stack_trace(&entry->stacktrace); + entry->stack_len = stack_trace_save(entry->stack_entries, + ARRAY_SIZE(entry->stack_entries), + 1); #endif - return entry; } diff --git a/kernel/events/core.c b/kernel/events/core.c index 72d06e302e99..dc7dead2d2cc 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2009,8 +2009,8 @@ event_sched_out(struct perf_event *event, event->pmu->del(event, 0); event->oncpu = -1; - if (event->pending_disable) { - event->pending_disable = 0; + if (READ_ONCE(event->pending_disable) >= 0) { + WRITE_ONCE(event->pending_disable, -1); state = PERF_EVENT_STATE_OFF; } perf_event_set_state(event, state); @@ -2198,7 +2198,8 @@ EXPORT_SYMBOL_GPL(perf_event_disable); void perf_event_disable_inatomic(struct perf_event *event) { - event->pending_disable = 1; + WRITE_ONCE(event->pending_disable, smp_processor_id()); + /* can fail, see perf_pending_event_disable() */ irq_work_queue(&event->pending); } @@ -5810,10 +5811,45 @@ void perf_event_wakeup(struct perf_event *event) } } +static void perf_pending_event_disable(struct perf_event *event) +{ + int cpu = READ_ONCE(event->pending_disable); + + if (cpu < 0) + return; + + if (cpu == smp_processor_id()) { + WRITE_ONCE(event->pending_disable, -1); + perf_event_disable_local(event); + return; + } + + /* + * CPU-A CPU-B + * + * perf_event_disable_inatomic() + * @pending_disable = CPU-A; + * irq_work_queue(); + * + * sched-out + * @pending_disable = -1; + * + * sched-in + * perf_event_disable_inatomic() + * @pending_disable = CPU-B; + * irq_work_queue(); // FAILS + * + * irq_work_run() + * perf_pending_event() + * + * But the event runs on CPU-B and wants disabling there. + */ + irq_work_queue_on(&event->pending, cpu); +} + static void perf_pending_event(struct irq_work *entry) { - struct perf_event *event = container_of(entry, - struct perf_event, pending); + struct perf_event *event = container_of(entry, struct perf_event, pending); int rctx; rctx = perf_swevent_get_recursion_context(); @@ -5822,10 +5858,7 @@ static void perf_pending_event(struct irq_work *entry) * and we won't recurse 'further'. */ - if (event->pending_disable) { - event->pending_disable = 0; - perf_event_disable_local(event); - } + perf_pending_event_disable(event); if (event->pending_wakeup) { event->pending_wakeup = 0; @@ -9044,26 +9077,29 @@ static void perf_event_addr_filters_apply(struct perf_event *event) if (task == TASK_TOMBSTONE) return; - if (!ifh->nr_file_filters) - return; - - mm = get_task_mm(event->ctx->task); - if (!mm) - goto restart; + if (ifh->nr_file_filters) { + mm = get_task_mm(event->ctx->task); + if (!mm) + goto restart; - down_read(&mm->mmap_sem); + down_read(&mm->mmap_sem); + } raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { - event->addr_filter_ranges[count].start = 0; - event->addr_filter_ranges[count].size = 0; + if (filter->path.dentry) { + /* + * Adjust base offset if the filter is associated to a + * binary that needs to be mapped: + */ + event->addr_filter_ranges[count].start = 0; + event->addr_filter_ranges[count].size = 0; - /* - * Adjust base offset if the filter is associated to a binary - * that needs to be mapped: - */ - if (filter->path.dentry) perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); + } else { + event->addr_filter_ranges[count].start = filter->offset; + event->addr_filter_ranges[count].size = filter->size; + } count++; } @@ -9071,9 +9107,11 @@ static void perf_event_addr_filters_apply(struct perf_event *event) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); - up_read(&mm->mmap_sem); + if (ifh->nr_file_filters) { + up_read(&mm->mmap_sem); - mmput(mm); + mmput(mm); + } restart: perf_event_stop(event, 1); @@ -10236,6 +10274,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, init_waitqueue_head(&event->waitq); + event->pending_disable = -1; init_irq_work(&event->pending, perf_pending_event); mutex_init(&event->mmap_mutex); diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index a4047321d7d8..674b35383491 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -392,7 +392,7 @@ void *perf_aux_output_begin(struct perf_output_handle *handle, * store that will be enabled on successful return */ if (!handle->size) { /* A, matches D */ - event->pending_disable = 1; + event->pending_disable = smp_processor_id(); perf_output_wakeup(handle); local_set(&rb->aux_nest, 0); goto err_put; @@ -455,24 +455,21 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) rb->aux_head += size; } - if (size || handle->aux_flags) { - /* - * Only send RECORD_AUX if we have something useful to communicate - * - * Note: the OVERWRITE records by themselves are not considered - * useful, as they don't communicate any *new* information, - * aside from the short-lived offset, that becomes history at - * the next event sched-in and therefore isn't useful. - * The userspace that needs to copy out AUX data in overwrite - * mode should know to use user_page::aux_head for the actual - * offset. So, from now on we don't output AUX records that - * have *only* OVERWRITE flag set. - */ - - if (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE) - perf_event_aux_event(handle->event, aux_head, size, - handle->aux_flags); - } + /* + * Only send RECORD_AUX if we have something useful to communicate + * + * Note: the OVERWRITE records by themselves are not considered + * useful, as they don't communicate any *new* information, + * aside from the short-lived offset, that becomes history at + * the next event sched-in and therefore isn't useful. + * The userspace that needs to copy out AUX data in overwrite + * mode should know to use user_page::aux_head for the actual + * offset. So, from now on we don't output AUX records that + * have *only* OVERWRITE flag set. + */ + if (size || (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE)) + perf_event_aux_event(handle->event, aux_head, size, + handle->aux_flags); rb->user_page->aux_head = rb->aux_head; if (rb_need_aux_wakeup(rb)) @@ -480,7 +477,7 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) if (wakeup) { if (handle->aux_flags & PERF_AUX_FLAG_TRUNCATED) - handle->event->pending_disable = 1; + handle->event->pending_disable = smp_processor_id(); perf_output_wakeup(handle); } @@ -613,8 +610,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event, * PMU requests more than one contiguous chunks of memory * for SW double buffering */ - if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_SW_DOUBLEBUF) && - !overwrite) { + if (!overwrite) { if (!max_order) return -EINVAL; diff --git a/kernel/iomem.c b/kernel/iomem.c index f7525e14ebc6..93c264444510 100644 --- a/kernel/iomem.c +++ b/kernel/iomem.c @@ -55,7 +55,7 @@ static void *try_ram_remap(resource_size_t offset, size_t size, * * MEMREMAP_WB - matches the default mapping for System RAM on * the architecture. This is usually a read-allocate write-back cache. - * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM + * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM * memremap() will bypass establishing a new mapping and instead return * a pointer into the direct map. * @@ -86,7 +86,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags) /* Try all mapping types requested until one returns non-NULL */ if (flags & MEMREMAP_WB) { /* - * MEMREMAP_WB is special in that it can be satisifed + * MEMREMAP_WB is special in that it can be satisfied * from the direct map. Some archs depend on the * capability of memremap() to autodetect cases where * the requested range is potentially in System RAM. diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 3faef4a77f71..51128bea3846 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -1449,6 +1449,10 @@ int irq_chip_set_vcpu_affinity_parent(struct irq_data *data, void *vcpu_info) int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on) { data = data->parent_data; + + if (data->chip->flags & IRQCHIP_SKIP_SET_WAKE) + return 0; + if (data->chip->irq_set_wake) return data->chip->irq_set_wake(data, on); diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 13539e12cd80..9f8a709337cf 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -558,6 +558,7 @@ int __init early_irq_init(void) alloc_masks(&desc[i], node); raw_spin_lock_init(&desc[i].lock); lockdep_set_class(&desc[i].lock, &irq_desc_lock_class); + mutex_init(&desc[i].request_mutex); desc_set_defaults(i, &desc[i], node, NULL, NULL); } return arch_early_irq_init(); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index c83e54727131..b1ea30a5540e 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -709,7 +709,6 @@ static void unoptimize_kprobe(struct kprobe *p, bool force) static int reuse_unused_kprobe(struct kprobe *ap) { struct optimized_kprobe *op; - int ret; /* * Unused kprobe MUST be on the way of delayed unoptimizing (means @@ -720,9 +719,8 @@ static int reuse_unused_kprobe(struct kprobe *ap) /* Enable the probe again */ ap->flags &= ~KPROBE_FLAG_DISABLED; /* Optimize it again (remove from op->list) */ - ret = kprobe_optready(ap); - if (ret) - return ret; + if (!kprobe_optready(ap)) + return -EINVAL; optimize_kprobe(ap); return 0; diff --git a/kernel/latencytop.c b/kernel/latencytop.c index 96b4179cee6a..99a5b5f46dc5 100644 --- a/kernel/latencytop.c +++ b/kernel/latencytop.c @@ -120,8 +120,8 @@ account_global_scheduler_latency(struct task_struct *tsk, break; } - /* 0 and ULONG_MAX entries mean end of backtrace: */ - if (record == 0 || record == ULONG_MAX) + /* 0 entry marks end of backtrace: */ + if (!record) break; } if (same) { @@ -141,20 +141,6 @@ account_global_scheduler_latency(struct task_struct *tsk, memcpy(&latency_record[i], lat, sizeof(struct latency_record)); } -/* - * Iterator to store a backtrace into a latency record entry - */ -static inline void store_stacktrace(struct task_struct *tsk, - struct latency_record *lat) -{ - struct stack_trace trace; - - memset(&trace, 0, sizeof(trace)); - trace.max_entries = LT_BACKTRACEDEPTH; - trace.entries = &lat->backtrace[0]; - save_stack_trace_tsk(tsk, &trace); -} - /** * __account_scheduler_latency - record an occurred latency * @tsk - the task struct of the task hitting the latency @@ -191,7 +177,8 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter) lat.count = 1; lat.time = usecs; lat.max = usecs; - store_stacktrace(tsk, &lat); + + stack_trace_save_tsk(tsk, lat.backtrace, LT_BACKTRACEDEPTH, 0); raw_spin_lock_irqsave(&latency_lock, flags); @@ -210,8 +197,8 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter) break; } - /* 0 and ULONG_MAX entries mean end of backtrace: */ - if (record == 0 || record == ULONG_MAX) + /* 0 entry is end of backtrace */ + if (!record) break; } if (same) { @@ -252,10 +239,10 @@ static int lstats_show(struct seq_file *m, void *v) lr->count, lr->time, lr->max); for (q = 0; q < LT_BACKTRACEDEPTH; q++) { unsigned long bt = lr->backtrace[q]; + if (!bt) break; - if (bt == ULONG_MAX) - break; + seq_printf(m, " %ps", (void *)bt); } seq_puts(m, "\n"); diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 9c89ae8b337a..c53370d596be 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -202,15 +202,15 @@ void klp_update_patch_state(struct task_struct *task) * Determine whether the given stack trace includes any references to a * to-be-patched or to-be-unpatched function. */ -static int klp_check_stack_func(struct klp_func *func, - struct stack_trace *trace) +static int klp_check_stack_func(struct klp_func *func, unsigned long *entries, + unsigned int nr_entries) { unsigned long func_addr, func_size, address; struct klp_ops *ops; int i; - for (i = 0; i < trace->nr_entries; i++) { - address = trace->entries[i]; + for (i = 0; i < nr_entries; i++) { + address = entries[i]; if (klp_target_state == KLP_UNPATCHED) { /* @@ -254,29 +254,25 @@ static int klp_check_stack_func(struct klp_func *func, static int klp_check_stack(struct task_struct *task, char *err_buf) { static unsigned long entries[MAX_STACK_ENTRIES]; - struct stack_trace trace; struct klp_object *obj; struct klp_func *func; - int ret; + int ret, nr_entries; - trace.skip = 0; - trace.nr_entries = 0; - trace.max_entries = MAX_STACK_ENTRIES; - trace.entries = entries; - ret = save_stack_trace_tsk_reliable(task, &trace); + ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries)); WARN_ON_ONCE(ret == -ENOSYS); - if (ret) { + if (ret < 0) { snprintf(err_buf, STACK_ERR_BUF_SIZE, "%s: %s:%d has an unreliable stack\n", __func__, task->comm, task->pid); return ret; } + nr_entries = ret; klp_for_each_object(klp_transition_patch, obj) { if (!obj->patched) continue; klp_for_each_func(obj, func) { - ret = klp_check_stack_func(func, &trace); + ret = klp_check_stack_func(func, entries, nr_entries); if (ret) { snprintf(err_buf, STACK_ERR_BUF_SIZE, "%s: %s:%d is sleeping on function %s\n", diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 34cdcbedda49..91c6b89f04df 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -434,29 +434,14 @@ static void print_lockdep_off(const char *bug_msg) #endif } -static int save_trace(struct stack_trace *trace) +static int save_trace(struct lock_trace *trace) { - trace->nr_entries = 0; - trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; - trace->entries = stack_trace + nr_stack_trace_entries; - - trace->skip = 3; - - save_stack_trace(trace); - - /* - * Some daft arches put -1 at the end to indicate its a full trace. - * - * <rant> this is buggy anyway, since it takes a whole extra entry so a - * complete trace that maxes out the entries provided will be reported - * as incomplete, friggin useless </rant> - */ - if (trace->nr_entries != 0 && - trace->entries[trace->nr_entries-1] == ULONG_MAX) - trace->nr_entries--; - - trace->max_entries = trace->nr_entries; + unsigned long *entries = stack_trace + nr_stack_trace_entries; + unsigned int max_entries; + trace->offset = nr_stack_trace_entries; + max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; + trace->nr_entries = stack_trace_save(entries, max_entries, 3); nr_stack_trace_entries += trace->nr_entries; if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { @@ -1207,7 +1192,7 @@ static struct lock_list *alloc_list_entry(void) static int add_lock_to_list(struct lock_class *this, struct lock_class *links_to, struct list_head *head, unsigned long ip, int distance, - struct stack_trace *trace) + struct lock_trace *trace) { struct lock_list *entry; /* @@ -1426,6 +1411,13 @@ static inline int __bfs_backwards(struct lock_list *src_entry, * checking. */ +static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) +{ + unsigned long *entries = stack_trace + trace->offset; + + stack_trace_print(entries, trace->nr_entries, spaces); +} + /* * Print a dependency chain entry (this is only done when a deadlock * has been detected): @@ -1438,8 +1430,7 @@ print_circular_bug_entry(struct lock_list *target, int depth) printk("\n-> #%u", depth); print_lock_name(target->class); printk(KERN_CONT ":\n"); - print_stack_trace(&target->trace, 6); - + print_lock_trace(&target->trace, 6); return 0; } @@ -1533,10 +1524,9 @@ static inline int class_equal(struct lock_list *entry, void *data) } static noinline int print_circular_bug(struct lock_list *this, - struct lock_list *target, - struct held_lock *check_src, - struct held_lock *check_tgt, - struct stack_trace *trace) + struct lock_list *target, + struct held_lock *check_src, + struct held_lock *check_tgt) { struct task_struct *curr = current; struct lock_list *parent; @@ -1752,7 +1742,7 @@ static void print_lock_class_header(struct lock_class *class, int depth) len += printk("%*s %s", depth, "", usage_str[bit]); len += printk(KERN_CONT " at:\n"); - print_stack_trace(class->usage_traces + bit, len); + print_lock_trace(class->usage_traces + bit, len); } } printk("%*s }\n", depth, ""); @@ -1777,7 +1767,7 @@ print_shortest_lock_dependencies(struct lock_list *leaf, do { print_lock_class_header(entry->class, depth); printk("%*s ... acquired at:\n", depth, ""); - print_stack_trace(&entry->trace, 2); + print_lock_trace(&entry->trace, 2); printk("\n"); if (depth == 0 && (entry != root)) { @@ -1890,14 +1880,14 @@ print_bad_irq_dependency(struct task_struct *curr, print_lock_name(backwards_entry->class); pr_warn("\n... which became %s-irq-safe at:\n", irqclass); - print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); + print_lock_trace(backwards_entry->class->usage_traces + bit1, 1); pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass); print_lock_name(forwards_entry->class); pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass); pr_warn("..."); - print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); + print_lock_trace(forwards_entry->class->usage_traces + bit2, 1); pr_warn("\nother info that might help us debug this:\n\n"); print_irq_lock_scenario(backwards_entry, forwards_entry, @@ -2170,8 +2160,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, */ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next, int distance, struct stack_trace *trace, - int (*save)(struct stack_trace *trace)) + struct held_lock *next, int distance, struct lock_trace *trace) { struct lock_list *uninitialized_var(target_entry); struct lock_list *entry; @@ -2209,15 +2198,15 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, this.parent = NULL; ret = check_noncircular(&this, hlock_class(prev), &target_entry); if (unlikely(!ret)) { - if (!trace->entries) { + if (!trace->nr_entries) { /* - * If @save fails here, the printing might trigger - * a WARN but because of the !nr_entries it should - * not do bad things. + * If save_trace fails here, the printing might + * trigger a WARN but because of the !nr_entries it + * should not do bad things. */ - save(trace); + save_trace(trace); } - return print_circular_bug(&this, target_entry, next, prev, trace); + return print_circular_bug(&this, target_entry, next, prev); } else if (unlikely(ret < 0)) return print_bfs_bug(ret); @@ -2265,7 +2254,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, return print_bfs_bug(ret); - if (!trace->entries && !save(trace)) + if (!trace->nr_entries && !save_trace(trace)) return 0; /* @@ -2297,14 +2286,9 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, static int check_prevs_add(struct task_struct *curr, struct held_lock *next) { + struct lock_trace trace = { .nr_entries = 0 }; int depth = curr->lockdep_depth; struct held_lock *hlock; - struct stack_trace trace = { - .nr_entries = 0, - .max_entries = 0, - .entries = NULL, - .skip = 0, - }; /* * Debugging checks. @@ -2330,7 +2314,8 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) * added: */ if (hlock->read != 2 && hlock->check) { - int ret = check_prev_add(curr, hlock, next, distance, &trace, save_trace); + int ret = check_prev_add(curr, hlock, next, distance, + &trace); if (!ret) return 0; @@ -2731,6 +2716,10 @@ static inline int validate_chain(struct task_struct *curr, { return 1; } + +static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) +{ +} #endif /* @@ -2827,7 +2816,7 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this, print_lock(this); pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]); - print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); + print_lock_trace(hlock_class(this)->usage_traces + prev_bit, 1); print_irqtrace_events(curr); pr_warn("\nother info that might help us debug this:\n"); @@ -4689,8 +4678,8 @@ static void free_zapped_rcu(struct rcu_head *ch) return; raw_local_irq_save(flags); - if (!graph_lock()) - goto out_irq; + arch_spin_lock(&lockdep_lock); + current->lockdep_recursion = 1; /* closed head */ pf = delayed_free.pf + (delayed_free.index ^ 1); @@ -4702,8 +4691,8 @@ static void free_zapped_rcu(struct rcu_head *ch) */ call_rcu_zapped(delayed_free.pf + delayed_free.index); - graph_unlock(); -out_irq: + current->lockdep_recursion = 0; + arch_spin_unlock(&lockdep_lock); raw_local_irq_restore(flags); } @@ -4744,21 +4733,17 @@ static void lockdep_free_key_range_reg(void *start, unsigned long size) { struct pending_free *pf; unsigned long flags; - int locked; init_data_structures_once(); raw_local_irq_save(flags); - locked = graph_lock(); - if (!locked) - goto out_irq; - + arch_spin_lock(&lockdep_lock); + current->lockdep_recursion = 1; pf = get_pending_free(); __lockdep_free_key_range(pf, start, size); call_rcu_zapped(pf); - - graph_unlock(); -out_irq: + current->lockdep_recursion = 0; + arch_spin_unlock(&lockdep_lock); raw_local_irq_restore(flags); /* diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index ad40a2617063..80a463d31a8d 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -829,7 +829,9 @@ static void lock_torture_cleanup(void) "End of test: SUCCESS"); kfree(cxt.lwsa); + cxt.lwsa = NULL; kfree(cxt.lrsa); + cxt.lrsa = NULL; end: torture_cleanup_end(); diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 771e93f9c43f..6f357f4fc859 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -29,6 +29,7 @@ #include <linux/hw_breakpoint.h> #include <linux/cn_proc.h> #include <linux/compat.h> +#include <linux/sched/signal.h> /* * Access another process' address space via ptrace. @@ -924,18 +925,26 @@ int ptrace_request(struct task_struct *child, long request, ret = ptrace_setsiginfo(child, &siginfo); break; - case PTRACE_GETSIGMASK: + case PTRACE_GETSIGMASK: { + sigset_t *mask; + if (addr != sizeof(sigset_t)) { ret = -EINVAL; break; } - if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) + if (test_tsk_restore_sigmask(child)) + mask = &child->saved_sigmask; + else + mask = &child->blocked; + + if (copy_to_user(datavp, mask, sizeof(sigset_t))) ret = -EFAULT; else ret = 0; break; + } case PTRACE_SETSIGMASK: { sigset_t new_set; @@ -961,6 +970,8 @@ int ptrace_request(struct task_struct *child, long request, child->blocked = new_set; spin_unlock_irq(&child->sighand->siglock); + clear_tsk_restore_sigmask(child); + ret = 0; break; } diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index acee72c0b24b..4b58c907b4b7 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -233,6 +233,7 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) #ifdef CONFIG_RCU_STALL_COMMON extern int rcu_cpu_stall_suppress; +extern int rcu_cpu_stall_timeout; int rcu_jiffies_till_stall_check(void); #define rcu_ftrace_dump_stall_suppress() \ diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index c29761152874..7a6890b23c5f 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -494,6 +494,10 @@ rcu_perf_cleanup(void) if (torture_cleanup_begin()) return; + if (!cur_ops) { + torture_cleanup_end(); + return; + } if (reader_tasks) { for (i = 0; i < nrealreaders; i++) @@ -614,6 +618,7 @@ rcu_perf_init(void) pr_cont("\n"); WARN_ON(!IS_MODULE(CONFIG_RCU_PERF_TEST)); firsterr = -EINVAL; + cur_ops = NULL; goto unwind; } if (cur_ops->init) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index f14d1b18a74f..efaa5b3f4d3f 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -299,7 +299,6 @@ struct rcu_torture_ops { int irq_capable; int can_boost; int extendables; - int ext_irq_conflict; const char *name; }; @@ -592,12 +591,7 @@ static void srcu_torture_init(void) static void srcu_torture_cleanup(void) { - static DEFINE_TORTURE_RANDOM(rand); - - if (torture_random(&rand) & 0x800) - cleanup_srcu_struct(&srcu_ctld); - else - cleanup_srcu_struct_quiesced(&srcu_ctld); + cleanup_srcu_struct(&srcu_ctld); srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ } @@ -1160,7 +1154,7 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) unsigned long randmask2 = randmask1 >> 3; WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT); - /* Most of the time lots of bits, half the time only one bit. */ + /* Mostly only one bit (need preemption!), sometimes lots of bits. */ if (!(randmask1 & 0x7)) mask = mask & randmask2; else @@ -1170,10 +1164,6 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) || (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH)))) mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; - if ((mask & RCUTORTURE_RDR_IRQ) && - !(mask & cur_ops->ext_irq_conflict) && - (oldmask & cur_ops->ext_irq_conflict)) - mask |= cur_ops->ext_irq_conflict; /* Or if readers object. */ return mask ?: RCUTORTURE_RDR_RCU; } @@ -1848,7 +1838,7 @@ static int rcutorture_oom_notify(struct notifier_block *self, WARN(1, "%s invoked upon OOM during forward-progress testing.\n", __func__); rcu_torture_fwd_cb_hist(); - rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat) / 2)); + rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat)) / 2); WRITE_ONCE(rcu_fwd_emergency_stop, true); smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ pr_info("%s: Freed %lu RCU callbacks.\n", @@ -2094,6 +2084,10 @@ rcu_torture_cleanup(void) cur_ops->cb_barrier(); return; } + if (!cur_ops) { + torture_cleanup_end(); + return; + } rcu_torture_barrier_cleanup(); torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task); @@ -2267,6 +2261,7 @@ rcu_torture_init(void) pr_cont("\n"); WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); firsterr = -EINVAL; + cur_ops = NULL; goto unwind; } if (cur_ops->fqs == NULL && fqs_duration != 0) { diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 5d4a39a6505a..44d6606b8325 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -76,19 +76,16 @@ EXPORT_SYMBOL_GPL(init_srcu_struct); * Must invoke this after you are finished using a given srcu_struct that * was initialized via init_srcu_struct(), else you leak memory. */ -void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced) +void cleanup_srcu_struct(struct srcu_struct *ssp) { WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]); - if (quiesced) - WARN_ON(work_pending(&ssp->srcu_work)); - else - flush_work(&ssp->srcu_work); + flush_work(&ssp->srcu_work); WARN_ON(ssp->srcu_gp_running); WARN_ON(ssp->srcu_gp_waiting); WARN_ON(ssp->srcu_cb_head); WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail); } -EXPORT_SYMBOL_GPL(_cleanup_srcu_struct); +EXPORT_SYMBOL_GPL(cleanup_srcu_struct); /* * Removes the count for the old reader from the appropriate element of diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index a60b8ba9e1ac..9b761e546de8 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -360,8 +360,14 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp) return SRCU_INTERVAL; } -/* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */ -void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced) +/** + * cleanup_srcu_struct - deconstruct a sleep-RCU structure + * @ssp: structure to clean up. + * + * Must invoke this after you are finished using a given srcu_struct that + * was initialized via init_srcu_struct(), else you leak memory. + */ +void cleanup_srcu_struct(struct srcu_struct *ssp) { int cpu; @@ -369,24 +375,14 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced) return; /* Just leak it! */ if (WARN_ON(srcu_readers_active(ssp))) return; /* Just leak it! */ - if (quiesced) { - if (WARN_ON(delayed_work_pending(&ssp->work))) - return; /* Just leak it! */ - } else { - flush_delayed_work(&ssp->work); - } + flush_delayed_work(&ssp->work); for_each_possible_cpu(cpu) { struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu); - if (quiesced) { - if (WARN_ON(timer_pending(&sdp->delay_work))) - return; /* Just leak it! */ - if (WARN_ON(work_pending(&sdp->work))) - return; /* Just leak it! */ - } else { - del_timer_sync(&sdp->delay_work); - flush_work(&sdp->work); - } + del_timer_sync(&sdp->delay_work); + flush_work(&sdp->work); + if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist))) + return; /* Forgot srcu_barrier(), so just leak it! */ } if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) || WARN_ON(srcu_readers_active(ssp))) { @@ -397,7 +393,7 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced) free_percpu(ssp->sda); ssp->sda = NULL; } -EXPORT_SYMBOL_GPL(_cleanup_srcu_struct); +EXPORT_SYMBOL_GPL(cleanup_srcu_struct); /* * Counts the new reader in the appropriate per-CPU element of the diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index 911bd9076d43..477b4eb44af5 100644 --- a/kernel/rcu/tiny.c +++ b/kernel/rcu/tiny.c @@ -52,7 +52,7 @@ void rcu_qs(void) local_irq_save(flags); if (rcu_ctrlblk.donetail != rcu_ctrlblk.curtail) { rcu_ctrlblk.donetail = rcu_ctrlblk.curtail; - raise_softirq(RCU_SOFTIRQ); + raise_softirq_irqoff(RCU_SOFTIRQ); } local_irq_restore(flags); } diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index acd6ccf56faf..ec77ec336f58 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -102,11 +102,6 @@ int rcu_num_lvls __read_mostly = RCU_NUM_LVLS; /* Number of rcu_nodes at specified level. */ int num_rcu_lvl[] = NUM_RCU_LVL_INIT; int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */ -/* panic() on RCU Stall sysctl. */ -int sysctl_panic_on_rcu_stall __read_mostly; -/* Commandeer a sysrq key to dump RCU's tree. */ -static bool sysrq_rcu; -module_param(sysrq_rcu, bool, 0444); /* * The rcu_scheduler_active variable is initialized to the value @@ -149,7 +144,7 @@ static void sync_sched_exp_online_cleanup(int cpu); /* rcuc/rcub kthread realtime priority */ static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0; -module_param(kthread_prio, int, 0644); +module_param(kthread_prio, int, 0444); /* Delay in jiffies for grace-period initialization delays, debug only. */ @@ -406,7 +401,7 @@ static bool rcu_kick_kthreads; */ static ulong jiffies_till_sched_qs = ULONG_MAX; module_param(jiffies_till_sched_qs, ulong, 0444); -static ulong jiffies_to_sched_qs; /* Adjusted version of above if not default */ +static ulong jiffies_to_sched_qs; /* See adjust_jiffies_till_sched_qs(). */ module_param(jiffies_to_sched_qs, ulong, 0444); /* Display only! */ /* @@ -424,6 +419,7 @@ static void adjust_jiffies_till_sched_qs(void) WRITE_ONCE(jiffies_to_sched_qs, jiffies_till_sched_qs); return; } + /* Otherwise, set to third fqs scan, but bound below on large system. */ j = READ_ONCE(jiffies_till_first_fqs) + 2 * READ_ONCE(jiffies_till_next_fqs); if (j < HZ / 10 + nr_cpu_ids / RCU_JIFFIES_FQS_DIV) @@ -513,74 +509,6 @@ static const char *gp_state_getname(short gs) } /* - * Show the state of the grace-period kthreads. - */ -void show_rcu_gp_kthreads(void) -{ - int cpu; - unsigned long j; - unsigned long ja; - unsigned long jr; - unsigned long jw; - struct rcu_data *rdp; - struct rcu_node *rnp; - - j = jiffies; - ja = j - READ_ONCE(rcu_state.gp_activity); - jr = j - READ_ONCE(rcu_state.gp_req_activity); - jw = j - READ_ONCE(rcu_state.gp_wake_time); - pr_info("%s: wait state: %s(%d) ->state: %#lx delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n", - rcu_state.name, gp_state_getname(rcu_state.gp_state), - rcu_state.gp_state, - rcu_state.gp_kthread ? rcu_state.gp_kthread->state : 0x1ffffL, - ja, jr, jw, (long)READ_ONCE(rcu_state.gp_wake_seq), - (long)READ_ONCE(rcu_state.gp_seq), - (long)READ_ONCE(rcu_get_root()->gp_seq_needed), - READ_ONCE(rcu_state.gp_flags)); - rcu_for_each_node_breadth_first(rnp) { - if (ULONG_CMP_GE(rcu_state.gp_seq, rnp->gp_seq_needed)) - continue; - pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld\n", - rnp->grplo, rnp->grphi, (long)rnp->gp_seq, - (long)rnp->gp_seq_needed); - if (!rcu_is_leaf_node(rnp)) - continue; - for_each_leaf_node_possible_cpu(rnp, cpu) { - rdp = per_cpu_ptr(&rcu_data, cpu); - if (rdp->gpwrap || - ULONG_CMP_GE(rcu_state.gp_seq, - rdp->gp_seq_needed)) - continue; - pr_info("\tcpu %d ->gp_seq_needed %ld\n", - cpu, (long)rdp->gp_seq_needed); - } - } - /* sched_show_task(rcu_state.gp_kthread); */ -} -EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads); - -/* Dump grace-period-request information due to commandeered sysrq. */ -static void sysrq_show_rcu(int key) -{ - show_rcu_gp_kthreads(); -} - -static struct sysrq_key_op sysrq_rcudump_op = { - .handler = sysrq_show_rcu, - .help_msg = "show-rcu(y)", - .action_msg = "Show RCU tree", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; - -static int __init rcu_sysrq_init(void) -{ - if (sysrq_rcu) - return register_sysrq_key('y', &sysrq_rcudump_op); - return 0; -} -early_initcall(rcu_sysrq_init); - -/* * Send along grace-period-related data for rcutorture diagnostics. */ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, @@ -1034,27 +962,6 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp) } /* - * Handler for the irq_work request posted when a grace period has - * gone on for too long, but not yet long enough for an RCU CPU - * stall warning. Set state appropriately, but just complain if - * there is unexpected state on entry. - */ -static void rcu_iw_handler(struct irq_work *iwp) -{ - struct rcu_data *rdp; - struct rcu_node *rnp; - - rdp = container_of(iwp, struct rcu_data, rcu_iw); - rnp = rdp->mynode; - raw_spin_lock_rcu_node(rnp); - if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) { - rdp->rcu_iw_gp_seq = rnp->gp_seq; - rdp->rcu_iw_pending = false; - } - raw_spin_unlock_rcu_node(rnp); -} - -/* * Return true if the specified CPU has passed through a quiescent * state by virtue of being in or having passed through an dynticks * idle state since the last call to dyntick_save_progress_counter() @@ -1167,295 +1074,6 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) return 0; } -static void record_gp_stall_check_time(void) -{ - unsigned long j = jiffies; - unsigned long j1; - - rcu_state.gp_start = j; - j1 = rcu_jiffies_till_stall_check(); - /* Record ->gp_start before ->jiffies_stall. */ - smp_store_release(&rcu_state.jiffies_stall, j + j1); /* ^^^ */ - rcu_state.jiffies_resched = j + j1 / 2; - rcu_state.n_force_qs_gpstart = READ_ONCE(rcu_state.n_force_qs); -} - -/* - * Complain about starvation of grace-period kthread. - */ -static void rcu_check_gp_kthread_starvation(void) -{ - struct task_struct *gpk = rcu_state.gp_kthread; - unsigned long j; - - j = jiffies - READ_ONCE(rcu_state.gp_activity); - if (j > 2 * HZ) { - pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n", - rcu_state.name, j, - (long)rcu_seq_current(&rcu_state.gp_seq), - READ_ONCE(rcu_state.gp_flags), - gp_state_getname(rcu_state.gp_state), rcu_state.gp_state, - gpk ? gpk->state : ~0, gpk ? task_cpu(gpk) : -1); - if (gpk) { - pr_err("RCU grace-period kthread stack dump:\n"); - sched_show_task(gpk); - wake_up_process(gpk); - } - } -} - -/* - * Dump stacks of all tasks running on stalled CPUs. First try using - * NMIs, but fall back to manual remote stack tracing on architectures - * that don't support NMI-based stack dumps. The NMI-triggered stack - * traces are more accurate because they are printed by the target CPU. - */ -static void rcu_dump_cpu_stacks(void) -{ - int cpu; - unsigned long flags; - struct rcu_node *rnp; - - rcu_for_each_leaf_node(rnp) { - raw_spin_lock_irqsave_rcu_node(rnp, flags); - for_each_leaf_node_possible_cpu(rnp, cpu) - if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) - if (!trigger_single_cpu_backtrace(cpu)) - dump_cpu_task(cpu); - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - } -} - -/* - * If too much time has passed in the current grace period, and if - * so configured, go kick the relevant kthreads. - */ -static void rcu_stall_kick_kthreads(void) -{ - unsigned long j; - - if (!rcu_kick_kthreads) - return; - j = READ_ONCE(rcu_state.jiffies_kick_kthreads); - if (time_after(jiffies, j) && rcu_state.gp_kthread && - (rcu_gp_in_progress() || READ_ONCE(rcu_state.gp_flags))) { - WARN_ONCE(1, "Kicking %s grace-period kthread\n", - rcu_state.name); - rcu_ftrace_dump(DUMP_ALL); - wake_up_process(rcu_state.gp_kthread); - WRITE_ONCE(rcu_state.jiffies_kick_kthreads, j + HZ); - } -} - -static void panic_on_rcu_stall(void) -{ - if (sysctl_panic_on_rcu_stall) - panic("RCU Stall\n"); -} - -static void print_other_cpu_stall(unsigned long gp_seq) -{ - int cpu; - unsigned long flags; - unsigned long gpa; - unsigned long j; - int ndetected = 0; - struct rcu_node *rnp = rcu_get_root(); - long totqlen = 0; - - /* Kick and suppress, if so configured. */ - rcu_stall_kick_kthreads(); - if (rcu_cpu_stall_suppress) - return; - - /* - * OK, time to rat on our buddy... - * See Documentation/RCU/stallwarn.txt for info on how to debug - * RCU CPU stall warnings. - */ - pr_err("INFO: %s detected stalls on CPUs/tasks:", rcu_state.name); - print_cpu_stall_info_begin(); - rcu_for_each_leaf_node(rnp) { - raw_spin_lock_irqsave_rcu_node(rnp, flags); - ndetected += rcu_print_task_stall(rnp); - if (rnp->qsmask != 0) { - for_each_leaf_node_possible_cpu(rnp, cpu) - if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) { - print_cpu_stall_info(cpu); - ndetected++; - } - } - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - } - - print_cpu_stall_info_end(); - for_each_possible_cpu(cpu) - totqlen += rcu_get_n_cbs_cpu(cpu); - pr_cont("(detected by %d, t=%ld jiffies, g=%ld, q=%lu)\n", - smp_processor_id(), (long)(jiffies - rcu_state.gp_start), - (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); - if (ndetected) { - rcu_dump_cpu_stacks(); - - /* Complain about tasks blocking the grace period. */ - rcu_print_detail_task_stall(); - } else { - if (rcu_seq_current(&rcu_state.gp_seq) != gp_seq) { - pr_err("INFO: Stall ended before state dump start\n"); - } else { - j = jiffies; - gpa = READ_ONCE(rcu_state.gp_activity); - pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n", - rcu_state.name, j - gpa, j, gpa, - READ_ONCE(jiffies_till_next_fqs), - rcu_get_root()->qsmask); - /* In this case, the current CPU might be at fault. */ - sched_show_task(current); - } - } - /* Rewrite if needed in case of slow consoles. */ - if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall))) - WRITE_ONCE(rcu_state.jiffies_stall, - jiffies + 3 * rcu_jiffies_till_stall_check() + 3); - - rcu_check_gp_kthread_starvation(); - - panic_on_rcu_stall(); - - rcu_force_quiescent_state(); /* Kick them all. */ -} - -static void print_cpu_stall(void) -{ - int cpu; - unsigned long flags; - struct rcu_data *rdp = this_cpu_ptr(&rcu_data); - struct rcu_node *rnp = rcu_get_root(); - long totqlen = 0; - - /* Kick and suppress, if so configured. */ - rcu_stall_kick_kthreads(); - if (rcu_cpu_stall_suppress) - return; - - /* - * OK, time to rat on ourselves... - * See Documentation/RCU/stallwarn.txt for info on how to debug - * RCU CPU stall warnings. - */ - pr_err("INFO: %s self-detected stall on CPU", rcu_state.name); - print_cpu_stall_info_begin(); - raw_spin_lock_irqsave_rcu_node(rdp->mynode, flags); - print_cpu_stall_info(smp_processor_id()); - raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags); - print_cpu_stall_info_end(); - for_each_possible_cpu(cpu) - totqlen += rcu_get_n_cbs_cpu(cpu); - pr_cont(" (t=%lu jiffies g=%ld q=%lu)\n", - jiffies - rcu_state.gp_start, - (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); - - rcu_check_gp_kthread_starvation(); - - rcu_dump_cpu_stacks(); - - raw_spin_lock_irqsave_rcu_node(rnp, flags); - /* Rewrite if needed in case of slow consoles. */ - if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall))) - WRITE_ONCE(rcu_state.jiffies_stall, - jiffies + 3 * rcu_jiffies_till_stall_check() + 3); - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - - panic_on_rcu_stall(); - - /* - * Attempt to revive the RCU machinery by forcing a context switch. - * - * A context switch would normally allow the RCU state machine to make - * progress and it could be we're stuck in kernel space without context - * switches for an entirely unreasonable amount of time. - */ - set_tsk_need_resched(current); - set_preempt_need_resched(); -} - -static void check_cpu_stall(struct rcu_data *rdp) -{ - unsigned long gs1; - unsigned long gs2; - unsigned long gps; - unsigned long j; - unsigned long jn; - unsigned long js; - struct rcu_node *rnp; - - if ((rcu_cpu_stall_suppress && !rcu_kick_kthreads) || - !rcu_gp_in_progress()) - return; - rcu_stall_kick_kthreads(); - j = jiffies; - - /* - * Lots of memory barriers to reject false positives. - * - * The idea is to pick up rcu_state.gp_seq, then - * rcu_state.jiffies_stall, then rcu_state.gp_start, and finally - * another copy of rcu_state.gp_seq. These values are updated in - * the opposite order with memory barriers (or equivalent) during - * grace-period initialization and cleanup. Now, a false positive - * can occur if we get an new value of rcu_state.gp_start and a old - * value of rcu_state.jiffies_stall. But given the memory barriers, - * the only way that this can happen is if one grace period ends - * and another starts between these two fetches. This is detected - * by comparing the second fetch of rcu_state.gp_seq with the - * previous fetch from rcu_state.gp_seq. - * - * Given this check, comparisons of jiffies, rcu_state.jiffies_stall, - * and rcu_state.gp_start suffice to forestall false positives. - */ - gs1 = READ_ONCE(rcu_state.gp_seq); - smp_rmb(); /* Pick up ->gp_seq first... */ - js = READ_ONCE(rcu_state.jiffies_stall); - smp_rmb(); /* ...then ->jiffies_stall before the rest... */ - gps = READ_ONCE(rcu_state.gp_start); - smp_rmb(); /* ...and finally ->gp_start before ->gp_seq again. */ - gs2 = READ_ONCE(rcu_state.gp_seq); - if (gs1 != gs2 || - ULONG_CMP_LT(j, js) || - ULONG_CMP_GE(gps, js)) - return; /* No stall or GP completed since entering function. */ - rnp = rdp->mynode; - jn = jiffies + 3 * rcu_jiffies_till_stall_check() + 3; - if (rcu_gp_in_progress() && - (READ_ONCE(rnp->qsmask) & rdp->grpmask) && - cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) { - - /* We haven't checked in, so go dump stack. */ - print_cpu_stall(); - - } else if (rcu_gp_in_progress() && - ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY) && - cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) { - - /* They had a few time units to dump stack, so complain. */ - print_other_cpu_stall(gs2); - } -} - -/** - * rcu_cpu_stall_reset - prevent further stall warnings in current grace period - * - * Set the stall-warning timeout way off into the future, thus preventing - * any RCU CPU stall-warning messages from appearing in the current set of - * RCU grace periods. - * - * The caller must disable hard irqs. - */ -void rcu_cpu_stall_reset(void) -{ - WRITE_ONCE(rcu_state.jiffies_stall, jiffies + ULONG_MAX / 2); -} - /* Trace-event wrapper function for trace_rcu_future_grace_period. */ static void trace_rcu_this_gp(struct rcu_node *rnp, struct rcu_data *rdp, unsigned long gp_seq_req, const char *s) @@ -1585,7 +1203,7 @@ static bool rcu_future_gp_cleanup(struct rcu_node *rnp) static void rcu_gp_kthread_wake(void) { if ((current == rcu_state.gp_kthread && - !in_interrupt() && !in_serving_softirq()) || + !in_irq() && !in_serving_softirq()) || !READ_ONCE(rcu_state.gp_flags) || !rcu_state.gp_kthread) return; @@ -2295,11 +1913,10 @@ rcu_report_qs_rdp(int cpu, struct rcu_data *rdp) return; } mask = rdp->grpmask; + rdp->core_needs_qs = false; if ((rnp->qsmask & mask) == 0) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } else { - rdp->core_needs_qs = false; - /* * This GP can't end until cpu checks in, so all of our * callbacks can be processed during the next GP. @@ -2548,11 +2165,11 @@ void rcu_sched_clock_irq(int user) } /* - * Scan the leaf rcu_node structures, processing dyntick state for any that - * have not yet encountered a quiescent state, using the function specified. - * Also initiate boosting for any threads blocked on the root rcu_node. - * - * The caller must have suppressed start of new grace periods. + * Scan the leaf rcu_node structures. For each structure on which all + * CPUs have reported a quiescent state and on which there are tasks + * blocking the current grace period, initiate RCU priority boosting. + * Otherwise, invoke the specified function to check dyntick state for + * each CPU that has not yet reported a quiescent state. */ static void force_qs_rnp(int (*f)(struct rcu_data *rdp)) { @@ -2635,101 +2252,6 @@ void rcu_force_quiescent_state(void) } EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); -/* - * This function checks for grace-period requests that fail to motivate - * RCU to come out of its idle mode. - */ -void -rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp, - const unsigned long gpssdelay) -{ - unsigned long flags; - unsigned long j; - struct rcu_node *rnp_root = rcu_get_root(); - static atomic_t warned = ATOMIC_INIT(0); - - if (!IS_ENABLED(CONFIG_PROVE_RCU) || rcu_gp_in_progress() || - ULONG_CMP_GE(rnp_root->gp_seq, rnp_root->gp_seq_needed)) - return; - j = jiffies; /* Expensive access, and in common case don't get here. */ - if (time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) || - time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) || - atomic_read(&warned)) - return; - - raw_spin_lock_irqsave_rcu_node(rnp, flags); - j = jiffies; - if (rcu_gp_in_progress() || - ULONG_CMP_GE(rnp_root->gp_seq, rnp_root->gp_seq_needed) || - time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) || - time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) || - atomic_read(&warned)) { - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - return; - } - /* Hold onto the leaf lock to make others see warned==1. */ - - if (rnp_root != rnp) - raw_spin_lock_rcu_node(rnp_root); /* irqs already disabled. */ - j = jiffies; - if (rcu_gp_in_progress() || - ULONG_CMP_GE(rnp_root->gp_seq, rnp_root->gp_seq_needed) || - time_before(j, rcu_state.gp_req_activity + gpssdelay) || - time_before(j, rcu_state.gp_activity + gpssdelay) || - atomic_xchg(&warned, 1)) { - raw_spin_unlock_rcu_node(rnp_root); /* irqs remain disabled. */ - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - return; - } - WARN_ON(1); - if (rnp_root != rnp) - raw_spin_unlock_rcu_node(rnp_root); - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - show_rcu_gp_kthreads(); -} - -/* - * Do a forward-progress check for rcutorture. This is normally invoked - * due to an OOM event. The argument "j" gives the time period during - * which rcutorture would like progress to have been made. - */ -void rcu_fwd_progress_check(unsigned long j) -{ - unsigned long cbs; - int cpu; - unsigned long max_cbs = 0; - int max_cpu = -1; - struct rcu_data *rdp; - - if (rcu_gp_in_progress()) { - pr_info("%s: GP age %lu jiffies\n", - __func__, jiffies - rcu_state.gp_start); - show_rcu_gp_kthreads(); - } else { - pr_info("%s: Last GP end %lu jiffies ago\n", - __func__, jiffies - rcu_state.gp_end); - preempt_disable(); - rdp = this_cpu_ptr(&rcu_data); - rcu_check_gp_start_stall(rdp->mynode, rdp, j); - preempt_enable(); - } - for_each_possible_cpu(cpu) { - cbs = rcu_get_n_cbs_cpu(cpu); - if (!cbs) - continue; - if (max_cpu < 0) - pr_info("%s: callbacks", __func__); - pr_cont(" %d: %lu", cpu, cbs); - if (cbs <= max_cbs) - continue; - max_cbs = cbs; - max_cpu = cpu; - } - if (max_cpu >= 0) - pr_cont("\n"); -} -EXPORT_SYMBOL_GPL(rcu_fwd_progress_check); - /* Perform RCU core processing work for the current CPU. */ static __latent_entropy void rcu_core(struct softirq_action *unused) { @@ -3559,13 +3081,11 @@ static int rcu_pm_notify(struct notifier_block *self, switch (action) { case PM_HIBERNATION_PREPARE: case PM_SUSPEND_PREPARE: - if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */ - rcu_expedite_gp(); + rcu_expedite_gp(); break; case PM_POST_HIBERNATION: case PM_POST_SUSPEND: - if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */ - rcu_unexpedite_gp(); + rcu_unexpedite_gp(); break; default: break; @@ -3742,8 +3262,7 @@ static void __init rcu_init_geometry(void) jiffies_till_first_fqs = d; if (jiffies_till_next_fqs == ULONG_MAX) jiffies_till_next_fqs = d; - if (jiffies_till_sched_qs == ULONG_MAX) - adjust_jiffies_till_sched_qs(); + adjust_jiffies_till_sched_qs(); /* If the compile-time values are accurate, just leave. */ if (rcu_fanout_leaf == RCU_FANOUT_LEAF && @@ -3858,5 +3377,6 @@ void __init rcu_init(void) srcu_init(); } +#include "tree_stall.h" #include "tree_exp.h" #include "tree_plugin.h" diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index bb4f995f2d3f..e253d11af3c4 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -393,15 +393,13 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name; int rcu_dynticks_snap(struct rcu_data *rdp); -/* Forward declarations for rcutree_plugin.h */ +/* Forward declarations for tree_plugin.h */ static void rcu_bootup_announce(void); static void rcu_qs(void); static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU static bool rcu_preempt_has_tasks(struct rcu_node *rnp); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ -static void rcu_print_detail_task_stall(void); -static int rcu_print_task_stall(struct rcu_node *rnp); static int rcu_print_task_exp_stall(struct rcu_node *rnp); static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); static void rcu_flavor_sched_clock_irq(int user); @@ -418,9 +416,6 @@ static void rcu_prepare_for_idle(void); static bool rcu_preempt_has_tasks(struct rcu_node *rnp); static bool rcu_preempt_need_deferred_qs(struct task_struct *t); static void rcu_preempt_deferred_qs(struct task_struct *t); -static void print_cpu_stall_info_begin(void); -static void print_cpu_stall_info(int cpu); -static void print_cpu_stall_info_end(void); static void zero_cpu_stall_ticks(struct rcu_data *rdp); static bool rcu_nocb_cpu_needs_barrier(int cpu); static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp); @@ -445,3 +440,10 @@ static void rcu_bind_gp_kthread(void); static bool rcu_nohz_full_cpu(void); static void rcu_dynticks_task_enter(void); static void rcu_dynticks_task_exit(void); + +/* Forward declarations for tree_stall.h */ +static void record_gp_stall_check_time(void); +static void rcu_iw_handler(struct irq_work *iwp); +static void check_cpu_stall(struct rcu_data *rdp); +static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp, + const unsigned long gpssdelay); diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 4c2a0189e748..9c990df880d1 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -10,6 +10,7 @@ #include <linux/lockdep.h> static void rcu_exp_handler(void *unused); +static int rcu_print_task_exp_stall(struct rcu_node *rnp); /* * Record the start of an expedited grace period. @@ -633,7 +634,7 @@ static void rcu_exp_handler(void *unused) raw_spin_lock_irqsave_rcu_node(rnp, flags); if (rnp->expmask & rdp->grpmask) { rdp->deferred_qs = true; - WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, true); + t->rcu_read_unlock_special.b.exp_hint = true; } raw_spin_unlock_irqrestore_rcu_node(rnp, flags); return; @@ -648,7 +649,7 @@ static void rcu_exp_handler(void *unused) * * If the CPU is fully enabled (or if some buggy RCU-preempt * read-side critical section is being used from idle), just - * invoke rcu_preempt_defer_qs() to immediately report the + * invoke rcu_preempt_deferred_qs() to immediately report the * quiescent state. We cannot use rcu_read_unlock_special() * because we are in an interrupt handler, which will cause that * function to take an early exit without doing anything. @@ -670,6 +671,27 @@ static void sync_sched_exp_online_cleanup(int cpu) { } +/* + * Scan the current list of tasks blocked within RCU read-side critical + * sections, printing out the tid of each that is blocking the current + * expedited grace period. + */ +static int rcu_print_task_exp_stall(struct rcu_node *rnp) +{ + struct task_struct *t; + int ndetected = 0; + + if (!rnp->exp_tasks) + return 0; + t = list_entry(rnp->exp_tasks->prev, + struct task_struct, rcu_node_entry); + list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) { + pr_cont(" P%d", t->pid); + ndetected++; + } + return ndetected; +} + #else /* #ifdef CONFIG_PREEMPT_RCU */ /* Invoked on each online non-idle CPU for expedited quiescent state. */ @@ -709,6 +731,16 @@ static void sync_sched_exp_online_cleanup(int cpu) WARN_ON_ONCE(ret); } +/* + * Because preemptible RCU does not exist, we never have to check for + * tasks blocked within RCU read-side critical sections that are + * blocking the current expedited grace period. + */ +static int rcu_print_task_exp_stall(struct rcu_node *rnp) +{ + return 0; +} + #endif /* #else #ifdef CONFIG_PREEMPT_RCU */ /** diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 97dba50f6fb2..1102765f91fd 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -285,7 +285,7 @@ static void rcu_qs(void) TPS("cpuqs")); __this_cpu_write(rcu_data.cpu_no_qs.b.norm, false); barrier(); /* Coordinate with rcu_flavor_sched_clock_irq(). */ - current->rcu_read_unlock_special.b.need_qs = false; + WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, false); } } @@ -643,100 +643,6 @@ static void rcu_read_unlock_special(struct task_struct *t) } /* - * Dump detailed information for all tasks blocking the current RCU - * grace period on the specified rcu_node structure. - */ -static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) -{ - unsigned long flags; - struct task_struct *t; - - raw_spin_lock_irqsave_rcu_node(rnp, flags); - if (!rcu_preempt_blocked_readers_cgp(rnp)) { - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - return; - } - t = list_entry(rnp->gp_tasks->prev, - struct task_struct, rcu_node_entry); - list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) { - /* - * We could be printing a lot while holding a spinlock. - * Avoid triggering hard lockup. - */ - touch_nmi_watchdog(); - sched_show_task(t); - } - raw_spin_unlock_irqrestore_rcu_node(rnp, flags); -} - -/* - * Dump detailed information for all tasks blocking the current RCU - * grace period. - */ -static void rcu_print_detail_task_stall(void) -{ - struct rcu_node *rnp = rcu_get_root(); - - rcu_print_detail_task_stall_rnp(rnp); - rcu_for_each_leaf_node(rnp) - rcu_print_detail_task_stall_rnp(rnp); -} - -static void rcu_print_task_stall_begin(struct rcu_node *rnp) -{ - pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):", - rnp->level, rnp->grplo, rnp->grphi); -} - -static void rcu_print_task_stall_end(void) -{ - pr_cont("\n"); -} - -/* - * Scan the current list of tasks blocked within RCU read-side critical - * sections, printing out the tid of each. - */ -static int rcu_print_task_stall(struct rcu_node *rnp) -{ - struct task_struct *t; - int ndetected = 0; - - if (!rcu_preempt_blocked_readers_cgp(rnp)) - return 0; - rcu_print_task_stall_begin(rnp); - t = list_entry(rnp->gp_tasks->prev, - struct task_struct, rcu_node_entry); - list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) { - pr_cont(" P%d", t->pid); - ndetected++; - } - rcu_print_task_stall_end(); - return ndetected; -} - -/* - * Scan the current list of tasks blocked within RCU read-side critical - * sections, printing out the tid of each that is blocking the current - * expedited grace period. - */ -static int rcu_print_task_exp_stall(struct rcu_node *rnp) -{ - struct task_struct *t; - int ndetected = 0; - - if (!rnp->exp_tasks) - return 0; - t = list_entry(rnp->exp_tasks->prev, - struct task_struct, rcu_node_entry); - list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) { - pr_cont(" P%d", t->pid); - ndetected++; - } - return ndetected; -} - -/* * Check that the list of blocked tasks for the newly completed grace * period is in fact empty. It is a serious bug to complete a grace * period that still has RCU readers blocked! This function must be @@ -804,19 +710,25 @@ static void rcu_flavor_sched_clock_irq(int user) /* * Check for a task exiting while in a preemptible-RCU read-side - * critical section, clean up if so. No need to issue warnings, - * as debug_check_no_locks_held() already does this if lockdep - * is enabled. + * critical section, clean up if so. No need to issue warnings, as + * debug_check_no_locks_held() already does this if lockdep is enabled. + * Besides, if this function does anything other than just immediately + * return, there was a bug of some sort. Spewing warnings from this + * function is like as not to simply obscure important prior warnings. */ void exit_rcu(void) { struct task_struct *t = current; - if (likely(list_empty(¤t->rcu_node_entry))) + if (unlikely(!list_empty(¤t->rcu_node_entry))) { + t->rcu_read_lock_nesting = 1; + barrier(); + WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true); + } else if (unlikely(t->rcu_read_lock_nesting)) { + t->rcu_read_lock_nesting = 1; + } else { return; - t->rcu_read_lock_nesting = 1; - barrier(); - t->rcu_read_unlock_special.b.blocked = true; + } __rcu_read_unlock(); rcu_preempt_deferred_qs(current); } @@ -980,33 +892,6 @@ static bool rcu_preempt_need_deferred_qs(struct task_struct *t) static void rcu_preempt_deferred_qs(struct task_struct *t) { } /* - * Because preemptible RCU does not exist, we never have to check for - * tasks blocked within RCU read-side critical sections. - */ -static void rcu_print_detail_task_stall(void) -{ -} - -/* - * Because preemptible RCU does not exist, we never have to check for - * tasks blocked within RCU read-side critical sections. - */ -static int rcu_print_task_stall(struct rcu_node *rnp) -{ - return 0; -} - -/* - * Because preemptible RCU does not exist, we never have to check for - * tasks blocked within RCU read-side critical sections that are - * blocking the current expedited grace period. - */ -static int rcu_print_task_exp_stall(struct rcu_node *rnp) -{ - return 0; -} - -/* * Because there is no preemptible RCU, there can be no readers blocked, * so there is no need to check for blocked tasks. So check only for * bogus qsmask values. @@ -1185,8 +1070,6 @@ static int rcu_boost_kthread(void *arg) static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { - struct task_struct *t; - raw_lockdep_assert_held_rcu_node(rnp); if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); @@ -1200,9 +1083,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags) if (rnp->exp_tasks == NULL) rnp->boost_tasks = rnp->gp_tasks; raw_spin_unlock_irqrestore_rcu_node(rnp, flags); - t = rnp->boost_kthread_task; - if (t) - rcu_wake_cond(t, rnp->boost_kthread_status); + rcu_wake_cond(rnp->boost_kthread_task, + rnp->boost_kthread_status); } else { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } @@ -1649,98 +1531,6 @@ static void rcu_cleanup_after_idle(void) #endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */ -#ifdef CONFIG_RCU_FAST_NO_HZ - -static void print_cpu_stall_fast_no_hz(char *cp, int cpu) -{ - struct rcu_data *rdp = &per_cpu(rcu_data, cpu); - - sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c", - rdp->last_accelerate & 0xffff, jiffies & 0xffff, - ".l"[rdp->all_lazy], - ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)], - ".D"[!rdp->tick_nohz_enabled_snap]); -} - -#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */ - -static void print_cpu_stall_fast_no_hz(char *cp, int cpu) -{ - *cp = '\0'; -} - -#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */ - -/* Initiate the stall-info list. */ -static void print_cpu_stall_info_begin(void) -{ - pr_cont("\n"); -} - -/* - * Print out diagnostic information for the specified stalled CPU. - * - * If the specified CPU is aware of the current RCU grace period, then - * print the number of scheduling clock interrupts the CPU has taken - * during the time that it has been aware. Otherwise, print the number - * of RCU grace periods that this CPU is ignorant of, for example, "1" - * if the CPU was aware of the previous grace period. - * - * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info. - */ -static void print_cpu_stall_info(int cpu) -{ - unsigned long delta; - char fast_no_hz[72]; - struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); - char *ticks_title; - unsigned long ticks_value; - - /* - * We could be printing a lot while holding a spinlock. Avoid - * triggering hard lockup. - */ - touch_nmi_watchdog(); - - ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq); - if (ticks_value) { - ticks_title = "GPs behind"; - } else { - ticks_title = "ticks this GP"; - ticks_value = rdp->ticks_this_gp; - } - print_cpu_stall_fast_no_hz(fast_no_hz, cpu); - delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq); - pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n", - cpu, - "O."[!!cpu_online(cpu)], - "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)], - "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)], - !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' : - rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' : - "!."[!delta], - ticks_value, ticks_title, - rcu_dynticks_snap(rdp) & 0xfff, - rdp->dynticks_nesting, rdp->dynticks_nmi_nesting, - rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu), - READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart, - fast_no_hz); -} - -/* Terminate the stall-info list. */ -static void print_cpu_stall_info_end(void) -{ - pr_err("\t"); -} - -/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */ -static void zero_cpu_stall_ticks(struct rcu_data *rdp) -{ - rdp->ticks_this_gp = 0; - rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id()); - WRITE_ONCE(rdp->last_fqs_resched, jiffies); -} - #ifdef CONFIG_RCU_NOCB_CPU /* @@ -1766,11 +1556,22 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp) */ -/* Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters. */ +/* + * Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters. + * The string after the "rcu_nocbs=" is either "all" for all CPUs, or a + * comma-separated list of CPUs and/or CPU ranges. If an invalid list is + * given, a warning is emitted and all CPUs are offloaded. + */ static int __init rcu_nocb_setup(char *str) { alloc_bootmem_cpumask_var(&rcu_nocb_mask); - cpulist_parse(str, rcu_nocb_mask); + if (!strcasecmp(str, "all")) + cpumask_setall(rcu_nocb_mask); + else + if (cpulist_parse(str, rcu_nocb_mask)) { + pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n"); + cpumask_setall(rcu_nocb_mask); + } return 1; } __setup("rcu_nocbs=", rcu_nocb_setup); diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h new file mode 100644 index 000000000000..f65a73a97323 --- /dev/null +++ b/kernel/rcu/tree_stall.h @@ -0,0 +1,709 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * RCU CPU stall warnings for normal RCU grace periods + * + * Copyright IBM Corporation, 2019 + * + * Author: Paul E. McKenney <paulmck@linux.ibm.com> + */ + +////////////////////////////////////////////////////////////////////////////// +// +// Controlling CPU stall warnings, including delay calculation. + +/* panic() on RCU Stall sysctl. */ +int sysctl_panic_on_rcu_stall __read_mostly; + +#ifdef CONFIG_PROVE_RCU +#define RCU_STALL_DELAY_DELTA (5 * HZ) +#else +#define RCU_STALL_DELAY_DELTA 0 +#endif + +/* Limit-check stall timeouts specified at boottime and runtime. */ +int rcu_jiffies_till_stall_check(void) +{ + int till_stall_check = READ_ONCE(rcu_cpu_stall_timeout); + + /* + * Limit check must be consistent with the Kconfig limits + * for CONFIG_RCU_CPU_STALL_TIMEOUT. + */ + if (till_stall_check < 3) { + WRITE_ONCE(rcu_cpu_stall_timeout, 3); + till_stall_check = 3; + } else if (till_stall_check > 300) { + WRITE_ONCE(rcu_cpu_stall_timeout, 300); + till_stall_check = 300; + } + return till_stall_check * HZ + RCU_STALL_DELAY_DELTA; +} +EXPORT_SYMBOL_GPL(rcu_jiffies_till_stall_check); + +/* Don't do RCU CPU stall warnings during long sysrq printouts. */ +void rcu_sysrq_start(void) +{ + if (!rcu_cpu_stall_suppress) + rcu_cpu_stall_suppress = 2; +} + +void rcu_sysrq_end(void) +{ + if (rcu_cpu_stall_suppress == 2) + rcu_cpu_stall_suppress = 0; +} + +/* Don't print RCU CPU stall warnings during a kernel panic. */ +static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) +{ + rcu_cpu_stall_suppress = 1; + return NOTIFY_DONE; +} + +static struct notifier_block rcu_panic_block = { + .notifier_call = rcu_panic, +}; + +static int __init check_cpu_stall_init(void) +{ + atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block); + return 0; +} +early_initcall(check_cpu_stall_init); + +/* If so specified via sysctl, panic, yielding cleaner stall-warning output. */ +static void panic_on_rcu_stall(void) +{ + if (sysctl_panic_on_rcu_stall) + panic("RCU Stall\n"); +} + +/** + * rcu_cpu_stall_reset - prevent further stall warnings in current grace period + * + * Set the stall-warning timeout way off into the future, thus preventing + * any RCU CPU stall-warning messages from appearing in the current set of + * RCU grace periods. + * + * The caller must disable hard irqs. + */ +void rcu_cpu_stall_reset(void) +{ + WRITE_ONCE(rcu_state.jiffies_stall, jiffies + ULONG_MAX / 2); +} + +////////////////////////////////////////////////////////////////////////////// +// +// Interaction with RCU grace periods + +/* Start of new grace period, so record stall time (and forcing times). */ +static void record_gp_stall_check_time(void) +{ + unsigned long j = jiffies; + unsigned long j1; + + rcu_state.gp_start = j; + j1 = rcu_jiffies_till_stall_check(); + /* Record ->gp_start before ->jiffies_stall. */ + smp_store_release(&rcu_state.jiffies_stall, j + j1); /* ^^^ */ + rcu_state.jiffies_resched = j + j1 / 2; + rcu_state.n_force_qs_gpstart = READ_ONCE(rcu_state.n_force_qs); +} + +/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */ +static void zero_cpu_stall_ticks(struct rcu_data *rdp) +{ + rdp->ticks_this_gp = 0; + rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id()); + WRITE_ONCE(rdp->last_fqs_resched, jiffies); +} + +/* + * If too much time has passed in the current grace period, and if + * so configured, go kick the relevant kthreads. + */ +static void rcu_stall_kick_kthreads(void) +{ + unsigned long j; + + if (!rcu_kick_kthreads) + return; + j = READ_ONCE(rcu_state.jiffies_kick_kthreads); + if (time_after(jiffies, j) && rcu_state.gp_kthread && + (rcu_gp_in_progress() || READ_ONCE(rcu_state.gp_flags))) { + WARN_ONCE(1, "Kicking %s grace-period kthread\n", + rcu_state.name); + rcu_ftrace_dump(DUMP_ALL); + wake_up_process(rcu_state.gp_kthread); + WRITE_ONCE(rcu_state.jiffies_kick_kthreads, j + HZ); + } +} + +/* + * Handler for the irq_work request posted about halfway into the RCU CPU + * stall timeout, and used to detect excessive irq disabling. Set state + * appropriately, but just complain if there is unexpected state on entry. + */ +static void rcu_iw_handler(struct irq_work *iwp) +{ + struct rcu_data *rdp; + struct rcu_node *rnp; + + rdp = container_of(iwp, struct rcu_data, rcu_iw); + rnp = rdp->mynode; + raw_spin_lock_rcu_node(rnp); + if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) { + rdp->rcu_iw_gp_seq = rnp->gp_seq; + rdp->rcu_iw_pending = false; + } + raw_spin_unlock_rcu_node(rnp); +} + +////////////////////////////////////////////////////////////////////////////// +// +// Printing RCU CPU stall warnings + +#ifdef CONFIG_PREEMPT + +/* + * Dump detailed information for all tasks blocking the current RCU + * grace period on the specified rcu_node structure. + */ +static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) +{ + unsigned long flags; + struct task_struct *t; + + raw_spin_lock_irqsave_rcu_node(rnp, flags); + if (!rcu_preempt_blocked_readers_cgp(rnp)) { + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + return; + } + t = list_entry(rnp->gp_tasks->prev, + struct task_struct, rcu_node_entry); + list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) { + /* + * We could be printing a lot while holding a spinlock. + * Avoid triggering hard lockup. + */ + touch_nmi_watchdog(); + sched_show_task(t); + } + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); +} + +/* + * Scan the current list of tasks blocked within RCU read-side critical + * sections, printing out the tid of each. + */ +static int rcu_print_task_stall(struct rcu_node *rnp) +{ + struct task_struct *t; + int ndetected = 0; + + if (!rcu_preempt_blocked_readers_cgp(rnp)) + return 0; + pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):", + rnp->level, rnp->grplo, rnp->grphi); + t = list_entry(rnp->gp_tasks->prev, + struct task_struct, rcu_node_entry); + list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) { + pr_cont(" P%d", t->pid); + ndetected++; + } + pr_cont("\n"); + return ndetected; +} + +#else /* #ifdef CONFIG_PREEMPT */ + +/* + * Because preemptible RCU does not exist, we never have to check for + * tasks blocked within RCU read-side critical sections. + */ +static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) +{ +} + +/* + * Because preemptible RCU does not exist, we never have to check for + * tasks blocked within RCU read-side critical sections. + */ +static int rcu_print_task_stall(struct rcu_node *rnp) +{ + return 0; +} +#endif /* #else #ifdef CONFIG_PREEMPT */ + +/* + * Dump stacks of all tasks running on stalled CPUs. First try using + * NMIs, but fall back to manual remote stack tracing on architectures + * that don't support NMI-based stack dumps. The NMI-triggered stack + * traces are more accurate because they are printed by the target CPU. + */ +static void rcu_dump_cpu_stacks(void) +{ + int cpu; + unsigned long flags; + struct rcu_node *rnp; + + rcu_for_each_leaf_node(rnp) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + for_each_leaf_node_possible_cpu(rnp, cpu) + if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) + if (!trigger_single_cpu_backtrace(cpu)) + dump_cpu_task(cpu); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } +} + +#ifdef CONFIG_RCU_FAST_NO_HZ + +static void print_cpu_stall_fast_no_hz(char *cp, int cpu) +{ + struct rcu_data *rdp = &per_cpu(rcu_data, cpu); + + sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c", + rdp->last_accelerate & 0xffff, jiffies & 0xffff, + ".l"[rdp->all_lazy], + ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)], + ".D"[!!rdp->tick_nohz_enabled_snap]); +} + +#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */ + +static void print_cpu_stall_fast_no_hz(char *cp, int cpu) +{ + *cp = '\0'; +} + +#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */ + +/* + * Print out diagnostic information for the specified stalled CPU. + * + * If the specified CPU is aware of the current RCU grace period, then + * print the number of scheduling clock interrupts the CPU has taken + * during the time that it has been aware. Otherwise, print the number + * of RCU grace periods that this CPU is ignorant of, for example, "1" + * if the CPU was aware of the previous grace period. + * + * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info. + */ +static void print_cpu_stall_info(int cpu) +{ + unsigned long delta; + char fast_no_hz[72]; + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + char *ticks_title; + unsigned long ticks_value; + + /* + * We could be printing a lot while holding a spinlock. Avoid + * triggering hard lockup. + */ + touch_nmi_watchdog(); + + ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq); + if (ticks_value) { + ticks_title = "GPs behind"; + } else { + ticks_title = "ticks this GP"; + ticks_value = rdp->ticks_this_gp; + } + print_cpu_stall_fast_no_hz(fast_no_hz, cpu); + delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq); + pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n", + cpu, + "O."[!!cpu_online(cpu)], + "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)], + "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)], + !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' : + rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' : + "!."[!delta], + ticks_value, ticks_title, + rcu_dynticks_snap(rdp) & 0xfff, + rdp->dynticks_nesting, rdp->dynticks_nmi_nesting, + rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu), + READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart, + fast_no_hz); +} + +/* Complain about starvation of grace-period kthread. */ +static void rcu_check_gp_kthread_starvation(void) +{ + struct task_struct *gpk = rcu_state.gp_kthread; + unsigned long j; + + j = jiffies - READ_ONCE(rcu_state.gp_activity); + if (j > 2 * HZ) { + pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n", + rcu_state.name, j, + (long)rcu_seq_current(&rcu_state.gp_seq), + READ_ONCE(rcu_state.gp_flags), + gp_state_getname(rcu_state.gp_state), rcu_state.gp_state, + gpk ? gpk->state : ~0, gpk ? task_cpu(gpk) : -1); + if (gpk) { + pr_err("RCU grace-period kthread stack dump:\n"); + sched_show_task(gpk); + wake_up_process(gpk); + } + } +} + +static void print_other_cpu_stall(unsigned long gp_seq) +{ + int cpu; + unsigned long flags; + unsigned long gpa; + unsigned long j; + int ndetected = 0; + struct rcu_node *rnp; + long totqlen = 0; + + /* Kick and suppress, if so configured. */ + rcu_stall_kick_kthreads(); + if (rcu_cpu_stall_suppress) + return; + + /* + * OK, time to rat on our buddy... + * See Documentation/RCU/stallwarn.txt for info on how to debug + * RCU CPU stall warnings. + */ + pr_err("INFO: %s detected stalls on CPUs/tasks:\n", rcu_state.name); + rcu_for_each_leaf_node(rnp) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + ndetected += rcu_print_task_stall(rnp); + if (rnp->qsmask != 0) { + for_each_leaf_node_possible_cpu(rnp, cpu) + if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) { + print_cpu_stall_info(cpu); + ndetected++; + } + } + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } + + for_each_possible_cpu(cpu) + totqlen += rcu_get_n_cbs_cpu(cpu); + pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu)\n", + smp_processor_id(), (long)(jiffies - rcu_state.gp_start), + (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); + if (ndetected) { + rcu_dump_cpu_stacks(); + + /* Complain about tasks blocking the grace period. */ + rcu_for_each_leaf_node(rnp) + rcu_print_detail_task_stall_rnp(rnp); + } else { + if (rcu_seq_current(&rcu_state.gp_seq) != gp_seq) { + pr_err("INFO: Stall ended before state dump start\n"); + } else { + j = jiffies; + gpa = READ_ONCE(rcu_state.gp_activity); + pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n", + rcu_state.name, j - gpa, j, gpa, + READ_ONCE(jiffies_till_next_fqs), + rcu_get_root()->qsmask); + /* In this case, the current CPU might be at fault. */ + sched_show_task(current); + } + } + /* Rewrite if needed in case of slow consoles. */ + if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall))) + WRITE_ONCE(rcu_state.jiffies_stall, + jiffies + 3 * rcu_jiffies_till_stall_check() + 3); + + rcu_check_gp_kthread_starvation(); + + panic_on_rcu_stall(); + + rcu_force_quiescent_state(); /* Kick them all. */ +} + +static void print_cpu_stall(void) +{ + int cpu; + unsigned long flags; + struct rcu_data *rdp = this_cpu_ptr(&rcu_data); + struct rcu_node *rnp = rcu_get_root(); + long totqlen = 0; + + /* Kick and suppress, if so configured. */ + rcu_stall_kick_kthreads(); + if (rcu_cpu_stall_suppress) + return; + + /* + * OK, time to rat on ourselves... + * See Documentation/RCU/stallwarn.txt for info on how to debug + * RCU CPU stall warnings. + */ + pr_err("INFO: %s self-detected stall on CPU\n", rcu_state.name); + raw_spin_lock_irqsave_rcu_node(rdp->mynode, flags); + print_cpu_stall_info(smp_processor_id()); + raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags); + for_each_possible_cpu(cpu) + totqlen += rcu_get_n_cbs_cpu(cpu); + pr_cont("\t(t=%lu jiffies g=%ld q=%lu)\n", + jiffies - rcu_state.gp_start, + (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); + + rcu_check_gp_kthread_starvation(); + + rcu_dump_cpu_stacks(); + + raw_spin_lock_irqsave_rcu_node(rnp, flags); + /* Rewrite if needed in case of slow consoles. */ + if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall))) + WRITE_ONCE(rcu_state.jiffies_stall, + jiffies + 3 * rcu_jiffies_till_stall_check() + 3); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + + panic_on_rcu_stall(); + + /* + * Attempt to revive the RCU machinery by forcing a context switch. + * + * A context switch would normally allow the RCU state machine to make + * progress and it could be we're stuck in kernel space without context + * switches for an entirely unreasonable amount of time. + */ + set_tsk_need_resched(current); + set_preempt_need_resched(); +} + +static void check_cpu_stall(struct rcu_data *rdp) +{ + unsigned long gs1; + unsigned long gs2; + unsigned long gps; + unsigned long j; + unsigned long jn; + unsigned long js; + struct rcu_node *rnp; + + if ((rcu_cpu_stall_suppress && !rcu_kick_kthreads) || + !rcu_gp_in_progress()) + return; + rcu_stall_kick_kthreads(); + j = jiffies; + + /* + * Lots of memory barriers to reject false positives. + * + * The idea is to pick up rcu_state.gp_seq, then + * rcu_state.jiffies_stall, then rcu_state.gp_start, and finally + * another copy of rcu_state.gp_seq. These values are updated in + * the opposite order with memory barriers (or equivalent) during + * grace-period initialization and cleanup. Now, a false positive + * can occur if we get an new value of rcu_state.gp_start and a old + * value of rcu_state.jiffies_stall. But given the memory barriers, + * the only way that this can happen is if one grace period ends + * and another starts between these two fetches. This is detected + * by comparing the second fetch of rcu_state.gp_seq with the + * previous fetch from rcu_state.gp_seq. + * + * Given this check, comparisons of jiffies, rcu_state.jiffies_stall, + * and rcu_state.gp_start suffice to forestall false positives. + */ + gs1 = READ_ONCE(rcu_state.gp_seq); + smp_rmb(); /* Pick up ->gp_seq first... */ + js = READ_ONCE(rcu_state.jiffies_stall); + smp_rmb(); /* ...then ->jiffies_stall before the rest... */ + gps = READ_ONCE(rcu_state.gp_start); + smp_rmb(); /* ...and finally ->gp_start before ->gp_seq again. */ + gs2 = READ_ONCE(rcu_state.gp_seq); + if (gs1 != gs2 || + ULONG_CMP_LT(j, js) || + ULONG_CMP_GE(gps, js)) + return; /* No stall or GP completed since entering function. */ + rnp = rdp->mynode; + jn = jiffies + 3 * rcu_jiffies_till_stall_check() + 3; + if (rcu_gp_in_progress() && + (READ_ONCE(rnp->qsmask) & rdp->grpmask) && + cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) { + + /* We haven't checked in, so go dump stack. */ + print_cpu_stall(); + + } else if (rcu_gp_in_progress() && + ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY) && + cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) { + + /* They had a few time units to dump stack, so complain. */ + print_other_cpu_stall(gs2); + } +} + +////////////////////////////////////////////////////////////////////////////// +// +// RCU forward-progress mechanisms, including of callback invocation. + + +/* + * Show the state of the grace-period kthreads. + */ +void show_rcu_gp_kthreads(void) +{ + int cpu; + unsigned long j; + unsigned long ja; + unsigned long jr; + unsigned long jw; + struct rcu_data *rdp; + struct rcu_node *rnp; + + j = jiffies; + ja = j - READ_ONCE(rcu_state.gp_activity); + jr = j - READ_ONCE(rcu_state.gp_req_activity); + jw = j - READ_ONCE(rcu_state.gp_wake_time); + pr_info("%s: wait state: %s(%d) ->state: %#lx delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n", + rcu_state.name, gp_state_getname(rcu_state.gp_state), + rcu_state.gp_state, + rcu_state.gp_kthread ? rcu_state.gp_kthread->state : 0x1ffffL, + ja, jr, jw, (long)READ_ONCE(rcu_state.gp_wake_seq), + (long)READ_ONCE(rcu_state.gp_seq), + (long)READ_ONCE(rcu_get_root()->gp_seq_needed), + READ_ONCE(rcu_state.gp_flags)); + rcu_for_each_node_breadth_first(rnp) { + if (ULONG_CMP_GE(rcu_state.gp_seq, rnp->gp_seq_needed)) + continue; + pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld\n", + rnp->grplo, rnp->grphi, (long)rnp->gp_seq, + (long)rnp->gp_seq_needed); + if (!rcu_is_leaf_node(rnp)) + continue; + for_each_leaf_node_possible_cpu(rnp, cpu) { + rdp = per_cpu_ptr(&rcu_data, cpu); + if (rdp->gpwrap || + ULONG_CMP_GE(rcu_state.gp_seq, + rdp->gp_seq_needed)) + continue; + pr_info("\tcpu %d ->gp_seq_needed %ld\n", + cpu, (long)rdp->gp_seq_needed); + } + } + /* sched_show_task(rcu_state.gp_kthread); */ +} +EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads); + +/* + * This function checks for grace-period requests that fail to motivate + * RCU to come out of its idle mode. + */ +static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp, + const unsigned long gpssdelay) +{ + unsigned long flags; + unsigned long j; + struct rcu_node *rnp_root = rcu_get_root(); + static atomic_t warned = ATOMIC_INIT(0); + + if (!IS_ENABLED(CONFIG_PROVE_RCU) || rcu_gp_in_progress() || + ULONG_CMP_GE(rnp_root->gp_seq, rnp_root->gp_seq_needed)) + return; + j = jiffies; /* Expensive access, and in common case don't get here. */ + if (time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) || + time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) || + atomic_read(&warned)) + return; + + raw_spin_lock_irqsave_rcu_node(rnp, flags); + j = jiffies; + if (rcu_gp_in_progress() || + ULONG_CMP_GE(rnp_root->gp_seq, rnp_root->gp_seq_needed) || + time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) || + time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) || + atomic_read(&warned)) { + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + return; + } + /* Hold onto the leaf lock to make others see warned==1. */ + + if (rnp_root != rnp) + raw_spin_lock_rcu_node(rnp_root); /* irqs already disabled. */ + j = jiffies; + if (rcu_gp_in_progress() || + ULONG_CMP_GE(rnp_root->gp_seq, rnp_root->gp_seq_needed) || + time_before(j, rcu_state.gp_req_activity + gpssdelay) || + time_before(j, rcu_state.gp_activity + gpssdelay) || + atomic_xchg(&warned, 1)) { + raw_spin_unlock_rcu_node(rnp_root); /* irqs remain disabled. */ + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + return; + } + WARN_ON(1); + if (rnp_root != rnp) + raw_spin_unlock_rcu_node(rnp_root); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + show_rcu_gp_kthreads(); +} + +/* + * Do a forward-progress check for rcutorture. This is normally invoked + * due to an OOM event. The argument "j" gives the time period during + * which rcutorture would like progress to have been made. + */ +void rcu_fwd_progress_check(unsigned long j) +{ + unsigned long cbs; + int cpu; + unsigned long max_cbs = 0; + int max_cpu = -1; + struct rcu_data *rdp; + + if (rcu_gp_in_progress()) { + pr_info("%s: GP age %lu jiffies\n", + __func__, jiffies - rcu_state.gp_start); + show_rcu_gp_kthreads(); + } else { + pr_info("%s: Last GP end %lu jiffies ago\n", + __func__, jiffies - rcu_state.gp_end); + preempt_disable(); + rdp = this_cpu_ptr(&rcu_data); + rcu_check_gp_start_stall(rdp->mynode, rdp, j); + preempt_enable(); + } + for_each_possible_cpu(cpu) { + cbs = rcu_get_n_cbs_cpu(cpu); + if (!cbs) + continue; + if (max_cpu < 0) + pr_info("%s: callbacks", __func__); + pr_cont(" %d: %lu", cpu, cbs); + if (cbs <= max_cbs) + continue; + max_cbs = cbs; + max_cpu = cpu; + } + if (max_cpu >= 0) + pr_cont("\n"); +} +EXPORT_SYMBOL_GPL(rcu_fwd_progress_check); + +/* Commandeer a sysrq key to dump RCU's tree. */ +static bool sysrq_rcu; +module_param(sysrq_rcu, bool, 0444); + +/* Dump grace-period-request information due to commandeered sysrq. */ +static void sysrq_show_rcu(int key) +{ + show_rcu_gp_kthreads(); +} + +static struct sysrq_key_op sysrq_rcudump_op = { + .handler = sysrq_show_rcu, + .help_msg = "show-rcu(y)", + .action_msg = "Show RCU tree", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + +static int __init rcu_sysrq_init(void) +{ + if (sysrq_rcu) + return register_sysrq_key('y', &sysrq_rcudump_op); + return 0; +} +early_initcall(rcu_sysrq_init); diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index cbaa976c5945..c3bf44ba42e5 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -424,68 +424,11 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read); #endif #ifdef CONFIG_RCU_STALL_COMMON - -#ifdef CONFIG_PROVE_RCU -#define RCU_STALL_DELAY_DELTA (5 * HZ) -#else -#define RCU_STALL_DELAY_DELTA 0 -#endif - int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */ EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress); -static int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT; - module_param(rcu_cpu_stall_suppress, int, 0644); +int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT; module_param(rcu_cpu_stall_timeout, int, 0644); - -int rcu_jiffies_till_stall_check(void) -{ - int till_stall_check = READ_ONCE(rcu_cpu_stall_timeout); - - /* - * Limit check must be consistent with the Kconfig limits - * for CONFIG_RCU_CPU_STALL_TIMEOUT. - */ - if (till_stall_check < 3) { - WRITE_ONCE(rcu_cpu_stall_timeout, 3); - till_stall_check = 3; - } else if (till_stall_check > 300) { - WRITE_ONCE(rcu_cpu_stall_timeout, 300); - till_stall_check = 300; - } - return till_stall_check * HZ + RCU_STALL_DELAY_DELTA; -} -EXPORT_SYMBOL_GPL(rcu_jiffies_till_stall_check); - -void rcu_sysrq_start(void) -{ - if (!rcu_cpu_stall_suppress) - rcu_cpu_stall_suppress = 2; -} - -void rcu_sysrq_end(void) -{ - if (rcu_cpu_stall_suppress == 2) - rcu_cpu_stall_suppress = 0; -} - -static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) -{ - rcu_cpu_stall_suppress = 1; - return NOTIFY_DONE; -} - -static struct notifier_block rcu_panic_block = { - .notifier_call = rcu_panic, -}; - -static int __init check_cpu_stall_init(void) -{ - atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block); - return 0; -} -early_initcall(check_cpu_stall_init); - #endif /* #ifdef CONFIG_RCU_STALL_COMMON */ #ifdef CONFIG_TASKS_RCU diff --git a/kernel/resource.c b/kernel/resource.c index 92190f62ebc5..8c15f846e8ef 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -520,21 +520,20 @@ EXPORT_SYMBOL_GPL(page_is_ram); int region_intersects(resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { - resource_size_t end = start + size - 1; + struct resource res; int type = 0; int other = 0; struct resource *p; + res.start = start; + res.end = start + size - 1; + read_lock(&resource_lock); for (p = iomem_resource.child; p ; p = p->sibling) { bool is_type = (((p->flags & flags) == flags) && ((desc == IORES_DESC_NONE) || (desc == p->desc))); - if (start >= p->start && start <= p->end) - is_type ? type++ : other++; - if (end >= p->start && end <= p->end) - is_type ? type++ : other++; - if (p->start >= start && p->end <= end) + if (resource_overlaps(p, &res)) is_type ? type++ : other++; } read_unlock(&resource_lock); diff --git a/kernel/rseq.c b/kernel/rseq.c index 25e9a7b60eba..9424ee90589e 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -254,8 +254,7 @@ static int rseq_ip_fixup(struct pt_regs *regs) * - signal delivery, * and return to user-space. * - * This is how we can ensure that the entire rseq critical section, - * consisting of both the C part and the assembly instruction sequence, + * This is how we can ensure that the entire rseq critical section * will issue the commit instruction only if executed atomically with * respect to other threads scheduled on the same CPU, and with respect * to signal handlers. @@ -314,7 +313,7 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, /* Unregister rseq for current thread. */ if (current->rseq != rseq || !current->rseq) return -EINVAL; - if (current->rseq_len != rseq_len) + if (rseq_len != sizeof(*rseq)) return -EINVAL; if (current->rseq_sig != sig) return -EPERM; @@ -322,7 +321,6 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, if (ret) return ret; current->rseq = NULL; - current->rseq_len = 0; current->rseq_sig = 0; return 0; } @@ -336,7 +334,7 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, * the provided address differs from the prior * one. */ - if (current->rseq != rseq || current->rseq_len != rseq_len) + if (current->rseq != rseq || rseq_len != sizeof(*rseq)) return -EINVAL; if (current->rseq_sig != sig) return -EPERM; @@ -354,7 +352,6 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, if (!access_ok(rseq, rseq_len)) return -EFAULT; current->rseq = rseq; - current->rseq_len = rseq_len; current->rseq_sig = sig; /* * If rseq was previously inactive, and has just been diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4778c48a7fda..ade3f2287d1f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1151,7 +1151,6 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, /* Need help from migration thread: drop lock and wait. */ task_rq_unlock(rq, p, &rf); stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); - tlb_migrate_finish(p->mm); return 0; } else if (task_on_rq_queued(p)) { /* diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 5c41ea367422..3638d2377e3c 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -771,6 +771,7 @@ out: return 0; fail: + kobject_put(&tunables->attr_set.kobj); policy->governor_data = NULL; sugov_tunables_free(tunables); diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 6a73e41a2016..43901fa3f269 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -252,7 +252,6 @@ static void task_non_contending(struct task_struct *p) if (dl_entity_is_special(dl_se)) return; - WARN_ON(hrtimer_active(&dl_se->inactive_timer)); WARN_ON(dl_se->dl_non_contending); zerolag_time = dl_se->deadline - @@ -269,7 +268,7 @@ static void task_non_contending(struct task_struct *p) * If the "0-lag time" already passed, decrease the active * utilization now, instead of starting a timer */ - if (zerolag_time < 0) { + if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) { if (dl_task(p)) sub_running_bw(dl_se, dl_rq); if (!dl_task(p) || p->state == TASK_DEAD) { diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index fdab7eb6f351..35f3ea375084 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2007,6 +2007,10 @@ static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period) if (p->last_task_numa_placement) { delta = runtime - p->last_sum_exec_runtime; *period = now - p->last_task_numa_placement; + + /* Avoid time going backwards, prevent potential divide error: */ + if (unlikely((s64)*period < 0)) + *period = 0; } else { delta = p->se.avg.load_sum; *period = LOAD_AVG_MAX; @@ -4885,6 +4889,8 @@ static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer) return HRTIMER_NORESTART; } +extern const u64 max_cfs_quota_period; + static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) { struct cfs_bandwidth *cfs_b = @@ -4892,6 +4898,7 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) unsigned long flags; int overrun; int idle = 0; + int count = 0; raw_spin_lock_irqsave(&cfs_b->lock, flags); for (;;) { @@ -4899,6 +4906,28 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) if (!overrun) break; + if (++count > 3) { + u64 new, old = ktime_to_ns(cfs_b->period); + + new = (old * 147) / 128; /* ~115% */ + new = min(new, max_cfs_quota_period); + + cfs_b->period = ns_to_ktime(new); + + /* since max is 1s, this is limited to 1e9^2, which fits in u64 */ + cfs_b->quota *= new; + cfs_b->quota = div64_u64(cfs_b->quota, old); + + pr_warn_ratelimited( + "cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us %lld, cfs_quota_us = %lld)\n", + smp_processor_id(), + div_u64(new, NSEC_PER_USEC), + div_u64(cfs_b->quota, NSEC_PER_USEC)); + + /* reset count so we don't come right back in here */ + count = 0; + } + idle = do_sched_cfs_period_timer(cfs_b, overrun, flags); } if (idle) @@ -7784,10 +7813,10 @@ static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq) if (cfs_rq->last_h_load_update == now) return; - cfs_rq->h_load_next = NULL; + WRITE_ONCE(cfs_rq->h_load_next, NULL); for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); - cfs_rq->h_load_next = se; + WRITE_ONCE(cfs_rq->h_load_next, se); if (cfs_rq->last_h_load_update == now) break; } @@ -7797,7 +7826,7 @@ static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq) cfs_rq->last_h_load_update = now; } - while ((se = cfs_rq->h_load_next) != NULL) { + while ((se = READ_ONCE(cfs_rq->h_load_next)) != NULL) { load = cfs_rq->h_load; load = div64_ul(load * se->avg.load_avg, cfs_rq_load_avg(cfs_rq) + 1); diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 54a0347ca812..3582eeb59893 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -149,7 +149,7 @@ static void populate_seccomp_data(struct seccomp_data *sd) sd->nr = syscall_get_nr(task, regs); sd->arch = syscall_get_arch(); - syscall_get_arguments(task, regs, 0, 6, args); + syscall_get_arguments(task, regs, args); sd->args[0] = args[0]; sd->args[1] = args[1]; sd->args[2] = args[2]; @@ -502,7 +502,10 @@ out: * * Caller must be holding current->sighand->siglock lock. * - * Returns 0 on success, -ve on error. + * Returns 0 on success, -ve on error, or + * - in TSYNC mode: the pid of a thread which was either not in the correct + * seccomp mode or did not have an ancestral seccomp filter + * - in NEW_LISTENER mode: the fd of the new listener */ static long seccomp_attach_filter(unsigned int flags, struct seccomp_filter *filter) @@ -1258,6 +1261,16 @@ static long seccomp_set_mode_filter(unsigned int flags, if (flags & ~SECCOMP_FILTER_FLAG_MASK) return -EINVAL; + /* + * In the successful case, NEW_LISTENER returns the new listener fd. + * But in the failure case, TSYNC returns the thread that died. If you + * combine these two flags, there's no way to tell whether something + * succeeded or failed. So, let's disallow this combination. + */ + if ((flags & SECCOMP_FILTER_FLAG_TSYNC) && + (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER)) + return -EINVAL; + /* Prepare the new filter before holding any locks. */ prepared = seccomp_prepare_user_filter(filter); if (IS_ERR(prepared)) @@ -1304,7 +1317,7 @@ out: mutex_unlock(¤t->signal->cred_guard_mutex); out_put_fd: if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { - if (ret < 0) { + if (ret) { listener_f->private_data = NULL; fput(listener_f); put_unused_fd(listener); diff --git a/kernel/signal.c b/kernel/signal.c index b7953934aa99..227ba170298e 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3581,7 +3581,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, if (flags) return -EINVAL; - f = fdget_raw(pidfd); + f = fdget(pidfd); if (!f.file) return -EBADF; @@ -3605,16 +3605,11 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, if (unlikely(sig != kinfo.si_signo)) goto err; + /* Only allow sending arbitrary signals to yourself. */ + ret = -EPERM; if ((task_pid(current) != pid) && - (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) { - /* Only allow sending arbitrary signals to yourself. */ - ret = -EPERM; - if (kinfo.si_code != SI_USER) - goto err; - - /* Turn this into a regular kill signal. */ - prepare_kill_siginfo(sig, &kinfo); - } + (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) + goto err; } else { prepare_kill_siginfo(sig, &kinfo); } diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index f8edee9c792d..27bafc1e271e 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -5,41 +5,56 @@ * * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> */ +#include <linux/sched/task_stack.h> +#include <linux/sched/debug.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/export.h> #include <linux/kallsyms.h> #include <linux/stacktrace.h> -void print_stack_trace(struct stack_trace *trace, int spaces) +/** + * stack_trace_print - Print the entries in the stack trace + * @entries: Pointer to storage array + * @nr_entries: Number of entries in the storage array + * @spaces: Number of leading spaces to print + */ +void stack_trace_print(unsigned long *entries, unsigned int nr_entries, + int spaces) { - int i; + unsigned int i; - if (WARN_ON(!trace->entries)) + if (WARN_ON(!entries)) return; - for (i = 0; i < trace->nr_entries; i++) - printk("%*c%pS\n", 1 + spaces, ' ', (void *)trace->entries[i]); + for (i = 0; i < nr_entries; i++) + printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]); } -EXPORT_SYMBOL_GPL(print_stack_trace); +EXPORT_SYMBOL_GPL(stack_trace_print); -int snprint_stack_trace(char *buf, size_t size, - struct stack_trace *trace, int spaces) +/** + * stack_trace_snprint - Print the entries in the stack trace into a buffer + * @buf: Pointer to the print buffer + * @size: Size of the print buffer + * @entries: Pointer to storage array + * @nr_entries: Number of entries in the storage array + * @spaces: Number of leading spaces to print + * + * Return: Number of bytes printed. + */ +int stack_trace_snprint(char *buf, size_t size, unsigned long *entries, + unsigned int nr_entries, int spaces) { - int i; - int generated; - int total = 0; + unsigned int generated, i, total = 0; - if (WARN_ON(!trace->entries)) + if (WARN_ON(!entries)) return 0; - for (i = 0; i < trace->nr_entries; i++) { + for (i = 0; i < nr_entries && size; i++) { generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ', - (void *)trace->entries[i]); + (void *)entries[i]); total += generated; - - /* Assume that generated isn't a negative number */ if (generated >= size) { buf += size; size = 0; @@ -51,7 +66,176 @@ int snprint_stack_trace(char *buf, size_t size, return total; } -EXPORT_SYMBOL_GPL(snprint_stack_trace); +EXPORT_SYMBOL_GPL(stack_trace_snprint); + +#ifdef CONFIG_ARCH_STACKWALK + +struct stacktrace_cookie { + unsigned long *store; + unsigned int size; + unsigned int skip; + unsigned int len; +}; + +static bool stack_trace_consume_entry(void *cookie, unsigned long addr, + bool reliable) +{ + struct stacktrace_cookie *c = cookie; + + if (c->len >= c->size) + return false; + + if (c->skip > 0) { + c->skip--; + return true; + } + c->store[c->len++] = addr; + return c->len < c->size; +} + +static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr, + bool reliable) +{ + if (in_sched_functions(addr)) + return true; + return stack_trace_consume_entry(cookie, addr, reliable); +} + +/** + * stack_trace_save - Save a stack trace into a storage array + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save(unsigned long *store, unsigned int size, + unsigned int skipnr) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + .skip = skipnr + 1, + }; + + arch_stack_walk(consume_entry, &c, current, NULL); + return c.len; +} +EXPORT_SYMBOL_GPL(stack_trace_save); + +/** + * stack_trace_save_tsk - Save a task stack trace into a storage array + * @task: The task to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store, + unsigned int size, unsigned int skipnr) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched; + struct stacktrace_cookie c = { + .store = store, + .size = size, + .skip = skipnr + 1, + }; + + if (!try_get_task_stack(tsk)) + return 0; + + arch_stack_walk(consume_entry, &c, tsk, NULL); + put_task_stack(tsk); + return c.len; +} + +/** + * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array + * @regs: Pointer to pt_regs to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store, + unsigned int size, unsigned int skipnr) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + .skip = skipnr, + }; + + arch_stack_walk(consume_entry, &c, current, regs); + return c.len; +} + +#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE +/** + * stack_trace_save_tsk_reliable - Save task stack with verification + * @tsk: Pointer to the task to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * + * Return: An error if it detects any unreliable features of the + * stack. Otherwise it guarantees that the stack trace is + * reliable and returns the number of entries stored. + * + * If the task is not 'current', the caller *must* ensure the task is inactive. + */ +int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, + unsigned int size) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + }; + int ret; + + /* + * If the task doesn't have a stack (e.g., a zombie), the stack is + * "reliably" empty. + */ + if (!try_get_task_stack(tsk)) + return 0; + + ret = arch_stack_walk_reliable(consume_entry, &c, tsk); + put_task_stack(tsk); + return ret; +} +#endif + +#ifdef CONFIG_USER_STACKTRACE_SUPPORT +/** + * stack_trace_save_user - Save a user space stack trace into a storage array + * @store: Pointer to storage array + * @size: Size of the storage array + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + }; + + /* Trace user stack if not a kernel thread */ + if (!current->mm) + return 0; + + arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + return c.len; +} +#endif + +#else /* CONFIG_ARCH_STACKWALK */ /* * Architectures that do not implement save_stack_trace_*() @@ -77,3 +261,118 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk, WARN_ONCE(1, KERN_INFO "save_stack_tsk_reliable() not implemented yet.\n"); return -ENOSYS; } + +/** + * stack_trace_save - Save a stack trace into a storage array + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored + */ +unsigned int stack_trace_save(unsigned long *store, unsigned int size, + unsigned int skipnr) +{ + struct stack_trace trace = { + .entries = store, + .max_entries = size, + .skip = skipnr + 1, + }; + + save_stack_trace(&trace); + return trace.nr_entries; +} +EXPORT_SYMBOL_GPL(stack_trace_save); + +/** + * stack_trace_save_tsk - Save a task stack trace into a storage array + * @task: The task to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored + */ +unsigned int stack_trace_save_tsk(struct task_struct *task, + unsigned long *store, unsigned int size, + unsigned int skipnr) +{ + struct stack_trace trace = { + .entries = store, + .max_entries = size, + .skip = skipnr + 1, + }; + + save_stack_trace_tsk(task, &trace); + return trace.nr_entries; +} + +/** + * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array + * @regs: Pointer to pt_regs to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored + */ +unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store, + unsigned int size, unsigned int skipnr) +{ + struct stack_trace trace = { + .entries = store, + .max_entries = size, + .skip = skipnr, + }; + + save_stack_trace_regs(regs, &trace); + return trace.nr_entries; +} + +#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE +/** + * stack_trace_save_tsk_reliable - Save task stack with verification + * @tsk: Pointer to the task to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * + * Return: An error if it detects any unreliable features of the + * stack. Otherwise it guarantees that the stack trace is + * reliable and returns the number of entries stored. + * + * If the task is not 'current', the caller *must* ensure the task is inactive. + */ +int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, + unsigned int size) +{ + struct stack_trace trace = { + .entries = store, + .max_entries = size, + }; + int ret = save_stack_trace_tsk_reliable(tsk, &trace); + + return ret ? ret : trace.nr_entries; +} +#endif + +#ifdef CONFIG_USER_STACKTRACE_SUPPORT +/** + * stack_trace_save_user - Save a user space stack trace into a storage array + * @store: Pointer to storage array + * @size: Size of the storage array + * + * Return: Number of trace entries stored + */ +unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) +{ + struct stack_trace trace = { + .entries = store, + .max_entries = size, + }; + + save_stack_trace_user(&trace); + return trace.nr_entries; +} +#endif /* CONFIG_USER_STACKTRACE_SUPPORT */ + +#endif /* !CONFIG_ARCH_STACKWALK */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index e5da394d1ca3..c9ec050bcf46 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -128,6 +128,7 @@ static int zero; static int __maybe_unused one = 1; static int __maybe_unused two = 2; static int __maybe_unused four = 4; +static unsigned long zero_ul; static unsigned long one_ul = 1; static unsigned long long_max = LONG_MAX; static int one_hundred = 100; @@ -1750,7 +1751,7 @@ static struct ctl_table fs_table[] = { .maxlen = sizeof(files_stat.max_files), .mode = 0644, .proc_handler = proc_doulongvec_minmax, - .extra1 = &zero, + .extra1 = &zero_ul, .extra2 = &long_max, }, { diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 2c97e8c2d29f..0519a8805aab 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -594,7 +594,7 @@ static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now) { struct alarm *alarm = &timr->it.alarm.alarmtimer; - return ktime_sub(now, alarm->node.expires); + return ktime_sub(alarm->node.expires, now); } /** diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 094b82ca95e5..930113b9799a 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -272,7 +272,7 @@ static u64 notrace suspended_sched_clock_read(void) return cd.read_data[seq & 1].epoch_cyc; } -static int sched_clock_suspend(void) +int sched_clock_suspend(void) { struct clock_read_data *rd = &cd.read_data[0]; @@ -283,7 +283,7 @@ static int sched_clock_suspend(void) return 0; } -static void sched_clock_resume(void) +void sched_clock_resume(void) { struct clock_read_data *rd = &cd.read_data[0]; diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 529143b4c8d2..df401463a191 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -487,6 +487,7 @@ void tick_freeze(void) trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), true); system_state = SYSTEM_SUSPEND; + sched_clock_suspend(); timekeeping_suspend(); } else { tick_suspend_local(); @@ -510,6 +511,7 @@ void tick_unfreeze(void) if (tick_freeze_depth == num_online_cpus()) { timekeeping_resume(); + sched_clock_resume(); system_state = SYSTEM_RUNNING; trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), false); diff --git a/kernel/time/timekeeping.h b/kernel/time/timekeeping.h index 7a9b4eb7a1d5..141ab3ab0354 100644 --- a/kernel/time/timekeeping.h +++ b/kernel/time/timekeeping.h @@ -14,6 +14,13 @@ extern u64 timekeeping_max_deferment(void); extern void timekeeping_warp_clock(void); extern int timekeeping_suspend(void); extern void timekeeping_resume(void); +#ifdef CONFIG_GENERIC_SCHED_CLOCK +extern int sched_clock_suspend(void); +extern void sched_clock_resume(void); +#else +static inline int sched_clock_suspend(void) { return 0; } +static inline void sched_clock_resume(void) { } +#endif extern void do_timer(unsigned long ticks); extern void update_wall_time(void); diff --git a/kernel/torture.c b/kernel/torture.c index 8faa1a9aaeb9..17b2be9bde12 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -88,6 +88,8 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) return false; + if (num_online_cpus() <= 1) + return false; /* Can't offline the last CPU. */ if (verbose > 1) pr_alert("%s" TORTURE_FLAG diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 26c8ca9bd06b..b920358dd8f7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -33,6 +33,7 @@ #include <linux/list.h> #include <linux/hash.h> #include <linux/rcupdate.h> +#include <linux/kprobes.h> #include <trace/events/sched.h> @@ -6246,7 +6247,7 @@ void ftrace_reset_array_ops(struct trace_array *tr) tr->ops->func = ftrace_stub; } -static inline void +static nokprobe_inline void __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ignored, struct pt_regs *regs) { @@ -6306,11 +6307,13 @@ static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, { __ftrace_ops_list_func(ip, parent_ip, NULL, regs); } +NOKPROBE_SYMBOL(ftrace_ops_list_func); #else static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) { __ftrace_ops_list_func(ip, parent_ip, NULL, NULL); } +NOKPROBE_SYMBOL(ftrace_ops_no_ops); #endif /* @@ -6337,6 +6340,7 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, preempt_enable_notrace(); trace_clear_recursion(bit); } +NOKPROBE_SYMBOL(ftrace_ops_assist_func); /** * ftrace_ops_get_func - get the function a trampoline should call diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 41b6f96e5366..4ee8d8aa3d0f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -762,7 +762,7 @@ u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu) preempt_disable_notrace(); time = rb_time_stamp(buffer); - preempt_enable_no_resched_notrace(); + preempt_enable_notrace(); return time; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 21153e64bf1c..ec439999f387 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -159,6 +159,8 @@ static union trace_eval_map_item *trace_eval_maps; #endif /* CONFIG_TRACE_EVAL_MAP_FILE */ static int tracing_set_tracer(struct trace_array *tr, const char *buf); +static void ftrace_trace_userstack(struct ring_buffer *buffer, + unsigned long flags, int pc); #define MAX_TRACER_SIZE 100 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; @@ -496,8 +498,10 @@ int trace_pid_write(struct trace_pid_list *filtered_pids, * not modified. */ pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL); - if (!pid_list) + if (!pid_list) { + trace_parser_put(&parser); return -ENOMEM; + } pid_list->pid_max = READ_ONCE(pid_max); @@ -507,6 +511,7 @@ int trace_pid_write(struct trace_pid_list *filtered_pids, pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3); if (!pid_list->pids) { + trace_parser_put(&parser); kfree(pid_list); return -ENOMEM; } @@ -2749,12 +2754,21 @@ trace_function(struct trace_array *tr, #ifdef CONFIG_STACKTRACE -#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long)) +/* Allow 4 levels of nesting: normal, softirq, irq, NMI */ +#define FTRACE_KSTACK_NESTING 4 + +#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING) + struct ftrace_stack { - unsigned long calls[FTRACE_STACK_MAX_ENTRIES]; + unsigned long calls[FTRACE_KSTACK_ENTRIES]; }; -static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack); + +struct ftrace_stacks { + struct ftrace_stack stacks[FTRACE_KSTACK_NESTING]; +}; + +static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks); static DEFINE_PER_CPU(int, ftrace_stack_reserve); static void __ftrace_trace_stack(struct ring_buffer *buffer, @@ -2763,13 +2777,10 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, { struct trace_event_call *call = &event_kernel_stack; struct ring_buffer_event *event; + unsigned int size, nr_entries; + struct ftrace_stack *fstack; struct stack_entry *entry; - struct stack_trace trace; - int use_stack; - int size = FTRACE_STACK_ENTRIES; - - trace.nr_entries = 0; - trace.skip = skip; + int stackidx; /* * Add one, for this function and the call to save_stack_trace() @@ -2777,7 +2788,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, */ #ifndef CONFIG_UNWINDER_ORC if (!regs) - trace.skip++; + skip++; #endif /* @@ -2788,53 +2799,40 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, */ preempt_disable_notrace(); - use_stack = __this_cpu_inc_return(ftrace_stack_reserve); + stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1; + + /* This should never happen. If it does, yell once and skip */ + if (WARN_ON_ONCE(stackidx > FTRACE_KSTACK_NESTING)) + goto out; + /* - * We don't need any atomic variables, just a barrier. - * If an interrupt comes in, we don't care, because it would - * have exited and put the counter back to what we want. - * We just need a barrier to keep gcc from moving things - * around. + * The above __this_cpu_inc_return() is 'atomic' cpu local. An + * interrupt will either see the value pre increment or post + * increment. If the interrupt happens pre increment it will have + * restored the counter when it returns. We just need a barrier to + * keep gcc from moving things around. */ barrier(); - if (use_stack == 1) { - trace.entries = this_cpu_ptr(ftrace_stack.calls); - trace.max_entries = FTRACE_STACK_MAX_ENTRIES; - if (regs) - save_stack_trace_regs(regs, &trace); - else - save_stack_trace(&trace); - - if (trace.nr_entries > size) - size = trace.nr_entries; - } else - /* From now on, use_stack is a boolean */ - use_stack = 0; + fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx; + size = ARRAY_SIZE(fstack->calls); - size *= sizeof(unsigned long); + if (regs) { + nr_entries = stack_trace_save_regs(regs, fstack->calls, + size, skip); + } else { + nr_entries = stack_trace_save(fstack->calls, size, skip); + } + size = nr_entries * sizeof(unsigned long); event = __trace_buffer_lock_reserve(buffer, TRACE_STACK, sizeof(*entry) + size, flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); - memset(&entry->caller, 0, size); - - if (use_stack) - memcpy(&entry->caller, trace.entries, - trace.nr_entries * sizeof(unsigned long)); - else { - trace.max_entries = FTRACE_STACK_ENTRIES; - trace.entries = entry->caller; - if (regs) - save_stack_trace_regs(regs, &trace); - else - save_stack_trace(&trace); - } - - entry->size = trace.nr_entries; + memcpy(&entry->caller, fstack->calls, size); + entry->size = nr_entries; if (!call_filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); @@ -2904,15 +2902,15 @@ void trace_dump_stack(int skip) } EXPORT_SYMBOL_GPL(trace_dump_stack); +#ifdef CONFIG_USER_STACKTRACE_SUPPORT static DEFINE_PER_CPU(int, user_stack_count); -void +static void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) { struct trace_event_call *call = &event_user_stack; struct ring_buffer_event *event; struct userstack_entry *entry; - struct stack_trace trace; if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE)) return; @@ -2943,12 +2941,7 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) entry->tgid = current->tgid; memset(&entry->caller, 0, sizeof(entry->caller)); - trace.nr_entries = 0; - trace.max_entries = FTRACE_STACK_ENTRIES; - trace.skip = 0; - trace.entries = entry->caller; - - save_stack_trace_user(&trace); + stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES); if (!call_filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); @@ -2957,13 +2950,12 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) out: preempt_enable(); } - -#ifdef UNUSED -static void __trace_userstack(struct trace_array *tr, unsigned long flags) +#else /* CONFIG_USER_STACKTRACE_SUPPORT */ +static void ftrace_trace_userstack(struct ring_buffer *buffer, + unsigned long flags, int pc) { - ftrace_trace_userstack(tr, flags, preempt_count()); } -#endif /* UNUSED */ +#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */ #endif /* CONFIG_STACKTRACE */ @@ -7025,35 +7017,43 @@ struct buffer_ref { struct ring_buffer *buffer; void *page; int cpu; - int ref; + refcount_t refcount; }; +static void buffer_ref_release(struct buffer_ref *ref) +{ + if (!refcount_dec_and_test(&ref->refcount)) + return; + ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page); + kfree(ref); +} + static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct buffer_ref *ref = (struct buffer_ref *)buf->private; - if (--ref->ref) - return; - - ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page); - kfree(ref); + buffer_ref_release(ref); buf->private = 0; } -static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, +static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct buffer_ref *ref = (struct buffer_ref *)buf->private; - ref->ref++; + if (refcount_read(&ref->refcount) > INT_MAX/2) + return false; + + refcount_inc(&ref->refcount); + return true; } /* Pipe buffer operations for a buffer. */ static const struct pipe_buf_operations buffer_pipe_buf_ops = { .confirm = generic_pipe_buf_confirm, .release = buffer_pipe_buf_release, - .steal = generic_pipe_buf_steal, + .steal = generic_pipe_buf_nosteal, .get = buffer_pipe_buf_get, }; @@ -7066,11 +7066,7 @@ static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i) struct buffer_ref *ref = (struct buffer_ref *)spd->partial[i].private; - if (--ref->ref) - return; - - ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page); - kfree(ref); + buffer_ref_release(ref); spd->partial[i].private = 0; } @@ -7125,7 +7121,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, break; } - ref->ref = 1; + refcount_set(&ref->refcount, 1); ref->buffer = iter->trace_buffer->buffer; ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file); if (IS_ERR(ref->page)) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index d80cee49e0eb..639047b259d7 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -782,17 +782,9 @@ void update_max_tr_single(struct trace_array *tr, #endif /* CONFIG_TRACER_MAX_TRACE */ #ifdef CONFIG_STACKTRACE -void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, - int pc); - void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc); #else -static inline void ftrace_trace_userstack(struct ring_buffer *buffer, - unsigned long flags, int pc) -{ -} - static inline void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc) { diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 4ad967453b6f..3ea65cdff30d 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -205,6 +205,8 @@ void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect) void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect, int is_constant) { + unsigned long flags = user_access_save(); + /* A constant is always correct */ if (is_constant) { f->constant++; @@ -223,6 +225,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, f->data.correct++; else f->data.incorrect++; + + user_access_restore(flags); } EXPORT_SYMBOL(ftrace_likely_update); diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 795aa2038377..a1d20421f4b0 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5186,7 +5186,6 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec, u64 var_ref_vals[TRACING_MAP_VARS_MAX]; char compound_key[HIST_KEY_SIZE_MAX]; struct tracing_map_elt *elt = NULL; - struct stack_trace stacktrace; struct hist_field *key_field; u64 field_contents; void *key = NULL; @@ -5198,14 +5197,9 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec, key_field = hist_data->fields[i]; if (key_field->flags & HIST_FIELD_FL_STACKTRACE) { - stacktrace.max_entries = HIST_STACKTRACE_DEPTH; - stacktrace.entries = entries; - stacktrace.nr_entries = 0; - stacktrace.skip = HIST_STACKTRACE_SKIP; - - memset(stacktrace.entries, 0, HIST_STACKTRACE_SIZE); - save_stack_trace(&stacktrace); - + memset(entries, 0, HIST_STACKTRACE_SIZE); + stack_trace_save(entries, HIST_STACKTRACE_DEPTH, + HIST_STACKTRACE_SKIP); key = entries; } else { field_contents = key_field->fn(key_field, elt, rbe, rec); @@ -5246,7 +5240,7 @@ static void hist_trigger_stacktrace_print(struct seq_file *m, unsigned int i; for (i = 0; i < max_entries; i++) { - if (stacktrace_entries[i] == ULONG_MAX) + if (!stacktrace_entries[i]) return; seq_printf(m, "%*c", 1 + spaces, ' '); diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index eec648a0d673..5d16f73898db 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -18,44 +18,32 @@ #include "trace.h" -static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] = - { [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX }; -unsigned stack_trace_index[STACK_TRACE_ENTRIES]; +#define STACK_TRACE_ENTRIES 500 -/* - * Reserve one entry for the passed in ip. This will allow - * us to remove most or all of the stack size overhead - * added by the stack tracer itself. - */ -struct stack_trace stack_trace_max = { - .max_entries = STACK_TRACE_ENTRIES - 1, - .entries = &stack_dump_trace[0], -}; +static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES]; +static unsigned stack_trace_index[STACK_TRACE_ENTRIES]; -unsigned long stack_trace_max_size; -arch_spinlock_t stack_trace_max_lock = +static unsigned int stack_trace_nr_entries; +static unsigned long stack_trace_max_size; +static arch_spinlock_t stack_trace_max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; DEFINE_PER_CPU(int, disable_stack_tracer); static DEFINE_MUTEX(stack_sysctl_mutex); int stack_tracer_enabled; -static int last_stack_tracer_enabled; -void stack_trace_print(void) +static void print_max_stack(void) { long i; int size; pr_emerg(" Depth Size Location (%d entries)\n" " ----- ---- --------\n", - stack_trace_max.nr_entries); + stack_trace_nr_entries); - for (i = 0; i < stack_trace_max.nr_entries; i++) { - if (stack_dump_trace[i] == ULONG_MAX) - break; - if (i+1 == stack_trace_max.nr_entries || - stack_dump_trace[i+1] == ULONG_MAX) + for (i = 0; i < stack_trace_nr_entries; i++) { + if (i + 1 == stack_trace_nr_entries) size = stack_trace_index[i]; else size = stack_trace_index[i] - stack_trace_index[i+1]; @@ -65,16 +53,7 @@ void stack_trace_print(void) } } -/* - * When arch-specific code overrides this function, the following - * data should be filled up, assuming stack_trace_max_lock is held to - * prevent concurrent updates. - * stack_trace_index[] - * stack_trace_max - * stack_trace_max_size - */ -void __weak -check_stack(unsigned long ip, unsigned long *stack) +static void check_stack(unsigned long ip, unsigned long *stack) { unsigned long this_size, flags; unsigned long *p, *top, *start; static int tracer_frame; @@ -110,13 +89,12 @@ check_stack(unsigned long ip, unsigned long *stack) stack_trace_max_size = this_size; - stack_trace_max.nr_entries = 0; - stack_trace_max.skip = 0; - - save_stack_trace(&stack_trace_max); + stack_trace_nr_entries = stack_trace_save(stack_dump_trace, + ARRAY_SIZE(stack_dump_trace) - 1, + 0); /* Skip over the overhead of the stack tracer itself */ - for (i = 0; i < stack_trace_max.nr_entries; i++) { + for (i = 0; i < stack_trace_nr_entries; i++) { if (stack_dump_trace[i] == ip) break; } @@ -125,7 +103,7 @@ check_stack(unsigned long ip, unsigned long *stack) * Some archs may not have the passed in ip in the dump. * If that happens, we need to show everything. */ - if (i == stack_trace_max.nr_entries) + if (i == stack_trace_nr_entries) i = 0; /* @@ -143,15 +121,13 @@ check_stack(unsigned long ip, unsigned long *stack) * loop will only happen once. This code only takes place * on a new max, so it is far from a fast path. */ - while (i < stack_trace_max.nr_entries) { + while (i < stack_trace_nr_entries) { int found = 0; stack_trace_index[x] = this_size; p = start; - for (; p < top && i < stack_trace_max.nr_entries; p++) { - if (stack_dump_trace[i] == ULONG_MAX) - break; + for (; p < top && i < stack_trace_nr_entries; p++) { /* * The READ_ONCE_NOCHECK is used to let KASAN know that * this is not a stack-out-of-bounds error. @@ -182,12 +158,10 @@ check_stack(unsigned long ip, unsigned long *stack) i++; } - stack_trace_max.nr_entries = x; - for (; x < i; x++) - stack_dump_trace[x] = ULONG_MAX; + stack_trace_nr_entries = x; if (task_stack_end_corrupted(current)) { - stack_trace_print(); + print_max_stack(); BUG(); } @@ -286,7 +260,7 @@ __next(struct seq_file *m, loff_t *pos) { long n = *pos - 1; - if (n >= stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX) + if (n >= stack_trace_nr_entries) return NULL; m->private = (void *)n; @@ -350,7 +324,7 @@ static int t_show(struct seq_file *m, void *v) seq_printf(m, " Depth Size Location" " (%d entries)\n" " ----- ---- --------\n", - stack_trace_max.nr_entries); + stack_trace_nr_entries); if (!stack_tracer_enabled && !stack_trace_max_size) print_disabled(m); @@ -360,12 +334,10 @@ static int t_show(struct seq_file *m, void *v) i = *(long *)v; - if (i >= stack_trace_max.nr_entries || - stack_dump_trace[i] == ULONG_MAX) + if (i >= stack_trace_nr_entries) return 0; - if (i+1 == stack_trace_max.nr_entries || - stack_dump_trace[i+1] == ULONG_MAX) + if (i + 1 == stack_trace_nr_entries) size = stack_trace_index[i]; else size = stack_trace_index[i] - stack_trace_index[i+1]; @@ -422,23 +394,21 @@ stack_trace_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { + int was_enabled; int ret; mutex_lock(&stack_sysctl_mutex); + was_enabled = !!stack_tracer_enabled; ret = proc_dointvec(table, write, buffer, lenp, ppos); - if (ret || !write || - (last_stack_tracer_enabled == !!stack_tracer_enabled)) + if (ret || !write || (was_enabled == !!stack_tracer_enabled)) goto out; - last_stack_tracer_enabled = !!stack_tracer_enabled; - if (stack_tracer_enabled) register_ftrace_function(&trace_ops); else unregister_ftrace_function(&trace_ops); - out: mutex_unlock(&stack_sysctl_mutex); return ret; @@ -454,7 +424,6 @@ static __init int enable_stacktrace(char *str) strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE); stack_tracer_enabled = 1; - last_stack_tracer_enabled = 1; return 1; } __setup("stacktrace", enable_stacktrace); diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index f93a56d2db27..fa8fbff736d6 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -314,6 +314,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) struct ring_buffer_event *event; struct ring_buffer *buffer; unsigned long irq_flags; + unsigned long args[6]; int pc; int syscall_nr; int size; @@ -347,7 +348,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) entry = ring_buffer_event_data(event); entry->nr = syscall_nr; - syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); + syscall_get_arguments(current, regs, args); + memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args); event_trigger_unlock_commit(trace_file, buffer, event, entry, irq_flags, pc); @@ -583,6 +585,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) struct syscall_metadata *sys_data; struct syscall_trace_enter *rec; struct hlist_head *head; + unsigned long args[6]; bool valid_prog_array; int syscall_nr; int rctx; @@ -613,8 +616,8 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) return; rec->nr = syscall_nr; - syscall_get_arguments(current, regs, 0, sys_data->nb_args, - (unsigned long *)&rec->args); + syscall_get_arguments(current, regs, args); + memcpy(&rec->args, args, sizeof(unsigned long) * sys_data->nb_args); if ((valid_prog_array && !perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) || diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 403c9bd90413..6a5787233113 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -554,13 +554,15 @@ static void softlockup_start_all(void) int lockup_detector_online_cpu(unsigned int cpu) { - watchdog_enable(cpu); + if (cpumask_test_cpu(cpu, &watchdog_allowed_mask)) + watchdog_enable(cpu); return 0; } int lockup_detector_offline_cpu(unsigned int cpu) { - watchdog_disable(cpu); + if (cpumask_test_cpu(cpu, &watchdog_allowed_mask)) + watchdog_disable(cpu); return 0; } diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c index 71381168dede..247bf0b1582c 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -135,7 +135,8 @@ static void watchdog_overflow_callback(struct perf_event *event, if (__this_cpu_read(hard_watchdog_warn) == true) return; - pr_emerg("Watchdog detected hard LOCKUP on cpu %d", this_cpu); + pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n", + this_cpu); print_modules(); print_irqtrace_events(current); if (regs) |