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-rw-r--r--kernel/fork.c1012
1 files changed, 624 insertions, 388 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 86425305cd4a..08969f5aa38d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -37,12 +37,13 @@
#include <linux/fdtable.h>
#include <linux/iocontext.h>
#include <linux/key.h>
+#include <linux/kmsan.h>
#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/mmu_notifier.h>
#include <linux/fs.h>
#include <linux/mm.h>
-#include <linux/vmacache.h>
+#include <linux/mm_inline.h>
#include <linux/nsproxy.h>
#include <linux/capability.h>
#include <linux/cpu.h>
@@ -76,7 +77,6 @@
#include <linux/taskstats_kern.h>
#include <linux/random.h>
#include <linux/tty.h>
-#include <linux/blkdev.h>
#include <linux/fs_struct.h>
#include <linux/magic.h>
#include <linux/perf_event.h>
@@ -94,8 +94,10 @@
#include <linux/thread_info.h>
#include <linux/stackleak.h>
#include <linux/kasan.h>
+#include <linux/scs.h>
+#include <linux/io_uring.h>
+#include <linux/bpf.h>
-#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
@@ -183,7 +185,7 @@ static inline void free_task_struct(struct task_struct *tsk)
*/
# if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
-#ifdef CONFIG_VMAP_STACK
+# ifdef CONFIG_VMAP_STACK
/*
* vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
* flush. Try to minimize the number of calls by caching stacks.
@@ -191,6 +193,41 @@ static inline void free_task_struct(struct task_struct *tsk)
#define NR_CACHED_STACKS 2
static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
+struct vm_stack {
+ struct rcu_head rcu;
+ struct vm_struct *stack_vm_area;
+};
+
+static bool try_release_thread_stack_to_cache(struct vm_struct *vm)
+{
+ unsigned int i;
+
+ for (i = 0; i < NR_CACHED_STACKS; i++) {
+ if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) != NULL)
+ continue;
+ return true;
+ }
+ return false;
+}
+
+static void thread_stack_free_rcu(struct rcu_head *rh)
+{
+ struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu);
+
+ if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area))
+ return;
+
+ vfree(vm_stack);
+}
+
+static void thread_stack_delayed_free(struct task_struct *tsk)
+{
+ struct vm_stack *vm_stack = tsk->stack;
+
+ vm_stack->stack_vm_area = tsk->stack_vm_area;
+ call_rcu(&vm_stack->rcu, thread_stack_free_rcu);
+}
+
static int free_vm_stack_cache(unsigned int cpu)
{
struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu);
@@ -208,11 +245,35 @@ static int free_vm_stack_cache(unsigned int cpu)
return 0;
}
-#endif
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
+static int memcg_charge_kernel_stack(struct vm_struct *vm)
{
-#ifdef CONFIG_VMAP_STACK
+ int i;
+ int ret;
+
+ BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);
+ BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
+
+ for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
+ ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);
+ if (ret)
+ goto err;
+ }
+ return 0;
+err:
+ /*
+ * If memcg_kmem_charge_page() fails, page's memory cgroup pointer is
+ * NULL, and memcg_kmem_uncharge_page() in free_thread_stack() will
+ * ignore this page.
+ */
+ for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+ memcg_kmem_uncharge_page(vm->pages[i], 0);
+ return ret;
+}
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
+ struct vm_struct *vm;
void *stack;
int i;
@@ -224,15 +285,22 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
if (!s)
continue;
- /* Clear the KASAN shadow of the stack. */
- kasan_unpoison_shadow(s->addr, THREAD_SIZE);
+ /* Reset stack metadata. */
+ kasan_unpoison_range(s->addr, THREAD_SIZE);
+
+ stack = kasan_reset_tag(s->addr);
/* Clear stale pointers from reused stack. */
- memset(s->addr, 0, THREAD_SIZE);
+ memset(stack, 0, THREAD_SIZE);
+
+ if (memcg_charge_kernel_stack(s)) {
+ vfree(s->addr);
+ return -ENOMEM;
+ }
tsk->stack_vm_area = s;
- tsk->stack = s->addr;
- return s->addr;
+ tsk->stack = stack;
+ return 0;
}
/*
@@ -245,75 +313,96 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
THREADINFO_GFP & ~__GFP_ACCOUNT,
PAGE_KERNEL,
0, node, __builtin_return_address(0));
+ if (!stack)
+ return -ENOMEM;
+ vm = find_vm_area(stack);
+ if (memcg_charge_kernel_stack(vm)) {
+ vfree(stack);
+ return -ENOMEM;
+ }
/*
* We can't call find_vm_area() in interrupt context, and
* free_thread_stack() can be called in interrupt context,
* so cache the vm_struct.
*/
- if (stack) {
- tsk->stack_vm_area = find_vm_area(stack);
- tsk->stack = stack;
- }
- return stack;
-#else
+ tsk->stack_vm_area = vm;
+ stack = kasan_reset_tag(stack);
+ tsk->stack = stack;
+ return 0;
+}
+
+static void free_thread_stack(struct task_struct *tsk)
+{
+ if (!try_release_thread_stack_to_cache(tsk->stack_vm_area))
+ thread_stack_delayed_free(tsk);
+
+ tsk->stack = NULL;
+ tsk->stack_vm_area = NULL;
+}
+
+# else /* !CONFIG_VMAP_STACK */
+
+static void thread_stack_free_rcu(struct rcu_head *rh)
+{
+ __free_pages(virt_to_page(rh), THREAD_SIZE_ORDER);
+}
+
+static void thread_stack_delayed_free(struct task_struct *tsk)
+{
+ struct rcu_head *rh = tsk->stack;
+
+ call_rcu(rh, thread_stack_free_rcu);
+}
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
struct page *page = alloc_pages_node(node, THREADINFO_GFP,
THREAD_SIZE_ORDER);
if (likely(page)) {
- tsk->stack = page_address(page);
- return tsk->stack;
+ tsk->stack = kasan_reset_tag(page_address(page));
+ return 0;
}
- return NULL;
-#endif
+ return -ENOMEM;
}
-static inline void free_thread_stack(struct task_struct *tsk)
+static void free_thread_stack(struct task_struct *tsk)
{
-#ifdef CONFIG_VMAP_STACK
- struct vm_struct *vm = task_stack_vm_area(tsk);
-
- if (vm) {
- int i;
-
- for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
- mod_memcg_page_state(vm->pages[i],
- MEMCG_KERNEL_STACK_KB,
- -(int)(PAGE_SIZE / 1024));
+ thread_stack_delayed_free(tsk);
+ tsk->stack = NULL;
+}
- memcg_kmem_uncharge(vm->pages[i], 0);
- }
+# endif /* CONFIG_VMAP_STACK */
+# else /* !(THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)) */
- for (i = 0; i < NR_CACHED_STACKS; i++) {
- if (this_cpu_cmpxchg(cached_stacks[i],
- NULL, tsk->stack_vm_area) != NULL)
- continue;
+static struct kmem_cache *thread_stack_cache;
- return;
- }
+static void thread_stack_free_rcu(struct rcu_head *rh)
+{
+ kmem_cache_free(thread_stack_cache, rh);
+}
- vfree_atomic(tsk->stack);
- return;
- }
-#endif
+static void thread_stack_delayed_free(struct task_struct *tsk)
+{
+ struct rcu_head *rh = tsk->stack;
- __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER);
+ call_rcu(rh, thread_stack_free_rcu);
}
-# else
-static struct kmem_cache *thread_stack_cache;
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk,
- int node)
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
unsigned long *stack;
stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
+ stack = kasan_reset_tag(stack);
tsk->stack = stack;
- return stack;
+ return stack ? 0 : -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
{
- kmem_cache_free(thread_stack_cache, tsk->stack);
+ thread_stack_delayed_free(tsk);
+ tsk->stack = NULL;
}
void thread_stack_cache_init(void)
@@ -323,8 +412,26 @@ void thread_stack_cache_init(void)
THREAD_SIZE, NULL);
BUG_ON(thread_stack_cache == NULL);
}
-# endif
-#endif
+
+# endif /* THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) */
+#else /* CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
+ unsigned long *stack;
+
+ stack = arch_alloc_thread_stack_node(tsk, node);
+ tsk->stack = stack;
+ return stack ? 0 : -ENOMEM;
+}
+
+static void free_thread_stack(struct task_struct *tsk)
+{
+ arch_free_thread_stack(tsk);
+ tsk->stack = NULL;
+}
+
+#endif /* !CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
/* SLAB cache for signal_struct structures (tsk->signal) */
static struct kmem_cache *signal_cachep;
@@ -359,89 +466,63 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (new) {
- *new = *orig;
+ ASSERT_EXCLUSIVE_WRITER(orig->vm_flags);
+ ASSERT_EXCLUSIVE_WRITER(orig->vm_file);
+ /*
+ * orig->shared.rb may be modified concurrently, but the clone
+ * will be reinitialized.
+ */
+ *new = data_race(*orig);
INIT_LIST_HEAD(&new->anon_vma_chain);
+ dup_anon_vma_name(orig, new);
}
return new;
}
void vm_area_free(struct vm_area_struct *vma)
{
+ free_anon_vma_name(vma);
kmem_cache_free(vm_area_cachep, vma);
}
static void account_kernel_stack(struct task_struct *tsk, int account)
{
- void *stack = task_stack_page(tsk);
- struct vm_struct *vm = task_stack_vm_area(tsk);
-
- BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);
-
- if (vm) {
+ if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+ struct vm_struct *vm = task_stack_vm_area(tsk);
int i;
- BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
-
- for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
- mod_zone_page_state(page_zone(vm->pages[i]),
- NR_KERNEL_STACK_KB,
- PAGE_SIZE / 1024 * account);
- }
+ for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+ mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
+ account * (PAGE_SIZE / 1024));
} else {
- /*
- * All stack pages are in the same zone and belong to the
- * same memcg.
- */
- struct page *first_page = virt_to_page(stack);
+ void *stack = task_stack_page(tsk);
- mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB,
- THREAD_SIZE / 1024 * account);
-
- mod_memcg_page_state(first_page, MEMCG_KERNEL_STACK_KB,
- account * (THREAD_SIZE / 1024));
+ /* All stack pages are in the same node. */
+ mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB,
+ account * (THREAD_SIZE / 1024));
}
}
-static int memcg_charge_kernel_stack(struct task_struct *tsk)
+void exit_task_stack_account(struct task_struct *tsk)
{
-#ifdef CONFIG_VMAP_STACK
- struct vm_struct *vm = task_stack_vm_area(tsk);
- int ret;
+ account_kernel_stack(tsk, -1);
- if (vm) {
+ if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+ struct vm_struct *vm;
int i;
- for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
- /*
- * If memcg_kmem_charge() fails, page->mem_cgroup
- * pointer is NULL, and both memcg_kmem_uncharge()
- * and mod_memcg_page_state() in free_thread_stack()
- * will ignore this page. So it's safe.
- */
- ret = memcg_kmem_charge(vm->pages[i], GFP_KERNEL, 0);
- if (ret)
- return ret;
-
- mod_memcg_page_state(vm->pages[i],
- MEMCG_KERNEL_STACK_KB,
- PAGE_SIZE / 1024);
- }
+ vm = task_stack_vm_area(tsk);
+ for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+ memcg_kmem_uncharge_page(vm->pages[i], 0);
}
-#endif
- return 0;
}
static void release_task_stack(struct task_struct *tsk)
{
- if (WARN_ON(tsk->state != TASK_DEAD))
+ if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD))
return; /* Better to leak the stack than to free prematurely */
- account_kernel_stack(tsk, -1);
free_thread_stack(tsk);
- tsk->stack = NULL;
-#ifdef CONFIG_VMAP_STACK
- tsk->stack_vm_area = NULL;
-#endif
}
#ifdef CONFIG_THREAD_INFO_IN_TASK
@@ -454,6 +535,9 @@ void put_task_stack(struct task_struct *tsk)
void free_task(struct task_struct *tsk)
{
+ release_user_cpus_ptr(tsk);
+ scs_release(tsk);
+
#ifndef CONFIG_THREAD_INFO_IN_TASK
/*
* The task is finally done with both the stack and thread_info,
@@ -469,7 +553,6 @@ void free_task(struct task_struct *tsk)
#endif
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
- put_seccomp_filter(tsk);
arch_release_task_struct(tsk);
if (tsk->flags & PF_KTHREAD)
free_kthread_struct(tsk);
@@ -477,18 +560,33 @@ void free_task(struct task_struct *tsk)
}
EXPORT_SYMBOL(free_task);
+static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm)
+{
+ struct file *exe_file;
+
+ exe_file = get_mm_exe_file(oldmm);
+ RCU_INIT_POINTER(mm->exe_file, exe_file);
+ /*
+ * We depend on the oldmm having properly denied write access to the
+ * exe_file already.
+ */
+ if (exe_file && deny_write_access(exe_file))
+ pr_warn_once("deny_write_access() failed in %s\n", __func__);
+}
+
#ifdef CONFIG_MMU
static __latent_entropy int dup_mmap(struct mm_struct *mm,
struct mm_struct *oldmm)
{
- struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
- struct rb_node **rb_link, *rb_parent;
+ struct vm_area_struct *mpnt, *tmp;
int retval;
- unsigned long charge;
+ unsigned long charge = 0;
LIST_HEAD(uf);
+ MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
+ MA_STATE(mas, &mm->mm_mt, 0, 0);
uprobe_start_dup_mmap();
- if (down_write_killable(&oldmm->mmap_sem)) {
+ if (mmap_write_lock_killable(oldmm)) {
retval = -EINTR;
goto fail_uprobe_end;
}
@@ -497,28 +595,26 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
/*
* Not linked in yet - no deadlock potential:
*/
- down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
+ mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);
/* No ordering required: file already has been exposed. */
- RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
+ dup_mm_exe_file(mm, oldmm);
mm->total_vm = oldmm->total_vm;
mm->data_vm = oldmm->data_vm;
mm->exec_vm = oldmm->exec_vm;
mm->stack_vm = oldmm->stack_vm;
- rb_link = &mm->mm_rb.rb_node;
- rb_parent = NULL;
- pprev = &mm->mmap;
retval = ksm_fork(mm, oldmm);
if (retval)
goto out;
- retval = khugepaged_fork(mm, oldmm);
+ khugepaged_fork(mm, oldmm);
+
+ retval = mas_expected_entries(&mas, oldmm->map_count);
if (retval)
goto out;
- prev = NULL;
- for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
+ mas_for_each(&old_mas, mpnt, ULONG_MAX) {
struct file *file;
if (mpnt->vm_flags & VM_DONTCOPY) {
@@ -532,7 +628,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
*/
if (fatal_signal_pending(current)) {
retval = -EINTR;
- goto out;
+ goto loop_out;
}
if (mpnt->vm_flags & VM_ACCOUNT) {
unsigned long len = vma_pages(mpnt);
@@ -552,25 +648,23 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
if (retval)
goto fail_nomem_anon_vma_fork;
if (tmp->vm_flags & VM_WIPEONFORK) {
- /* VM_WIPEONFORK gets a clean slate in the child. */
+ /*
+ * VM_WIPEONFORK gets a clean slate in the child.
+ * Don't prepare anon_vma until fault since we don't
+ * copy page for current vma.
+ */
tmp->anon_vma = NULL;
- if (anon_vma_prepare(tmp))
- goto fail_nomem_anon_vma_fork;
} else if (anon_vma_fork(tmp, mpnt))
goto fail_nomem_anon_vma_fork;
tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
- tmp->vm_next = tmp->vm_prev = NULL;
file = tmp->vm_file;
if (file) {
- struct inode *inode = file_inode(file);
struct address_space *mapping = file->f_mapping;
get_file(file);
- if (tmp->vm_flags & VM_DENYWRITE)
- atomic_dec(&inode->i_writecount);
i_mmap_lock_write(mapping);
if (tmp->vm_flags & VM_SHARED)
- atomic_inc(&mapping->i_mmap_writable);
+ mapping_allow_writable(mapping);
flush_dcache_mmap_lock(mapping);
/* insert tmp into the share list, just after mpnt */
vma_interval_tree_insert_after(tmp, mpnt,
@@ -580,45 +674,43 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
}
/*
- * Clear hugetlb-related page reserves for children. This only
- * affects MAP_PRIVATE mappings. Faults generated by the child
- * are not guaranteed to succeed, even if read-only
+ * Copy/update hugetlb private vma information.
*/
if (is_vm_hugetlb_page(tmp))
- reset_vma_resv_huge_pages(tmp);
-
- /*
- * Link in the new vma and copy the page table entries.
- */
- *pprev = tmp;
- pprev = &tmp->vm_next;
- tmp->vm_prev = prev;
- prev = tmp;
+ hugetlb_dup_vma_private(tmp);
- __vma_link_rb(mm, tmp, rb_link, rb_parent);
- rb_link = &tmp->vm_rb.rb_right;
- rb_parent = &tmp->vm_rb;
+ /* Link the vma into the MT */
+ mas.index = tmp->vm_start;
+ mas.last = tmp->vm_end - 1;
+ mas_store(&mas, tmp);
+ if (mas_is_err(&mas))
+ goto fail_nomem_mas_store;
mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
- retval = copy_page_range(mm, oldmm, mpnt);
+ retval = copy_page_range(tmp, mpnt);
if (tmp->vm_ops && tmp->vm_ops->open)
tmp->vm_ops->open(tmp);
if (retval)
- goto out;
+ goto loop_out;
}
/* a new mm has just been created */
retval = arch_dup_mmap(oldmm, mm);
+loop_out:
+ mas_destroy(&mas);
out:
- up_write(&mm->mmap_sem);
+ mmap_write_unlock(mm);
flush_tlb_mm(oldmm);
- up_write(&oldmm->mmap_sem);
+ mmap_write_unlock(oldmm);
dup_userfaultfd_complete(&uf);
fail_uprobe_end:
uprobe_end_dup_mmap();
return retval;
+
+fail_nomem_mas_store:
+ unlink_anon_vmas(tmp);
fail_nomem_anon_vma_fork:
mpol_put(vma_policy(tmp));
fail_nomem_policy:
@@ -626,7 +718,7 @@ fail_nomem_policy:
fail_nomem:
retval = -ENOMEM;
vm_unacct_memory(charge);
- goto out;
+ goto loop_out;
}
static inline int mm_alloc_pgd(struct mm_struct *mm)
@@ -644,9 +736,9 @@ static inline void mm_free_pgd(struct mm_struct *mm)
#else
static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
{
- down_write(&oldmm->mmap_sem);
- RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm));
- up_write(&oldmm->mmap_sem);
+ mmap_write_lock(oldmm);
+ dup_mm_exe_file(mm, oldmm);
+ mmap_write_unlock(oldmm);
return 0;
}
#define mm_alloc_pgd(mm) (0)
@@ -695,6 +787,7 @@ void __mmdrop(struct mm_struct *mm)
mmu_notifier_subscriptions_destroy(mm);
check_mm(mm);
put_user_ns(mm->user_ns);
+ mm_pasid_drop(mm);
free_mm(mm);
}
EXPORT_SYMBOL_GPL(__mmdrop);
@@ -740,15 +833,16 @@ void __put_task_struct(struct task_struct *tsk)
WARN_ON(refcount_read(&tsk->usage));
WARN_ON(tsk == current);
+ io_uring_free(tsk);
cgroup_free(tsk);
task_numa_free(tsk, true);
security_task_free(tsk);
+ bpf_task_storage_free(tsk);
exit_creds(tsk);
delayacct_tsk_free(tsk);
put_signal_struct(tsk->signal);
-
- if (!profile_handoff_task(tsk))
- free_task(tsk);
+ sched_core_free(tsk);
+ free_task(tsk);
}
EXPORT_SYMBOL_GPL(__put_task_struct);
@@ -828,15 +922,21 @@ void __init fork_init(void)
init_task.signal->rlim[RLIMIT_SIGPENDING] =
init_task.signal->rlim[RLIMIT_NPROC];
- for (i = 0; i < UCOUNT_COUNTS; i++) {
+ for (i = 0; i < UCOUNT_COUNTS; i++)
init_user_ns.ucount_max[i] = max_threads/2;
- }
+
+ set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY);
+ set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY);
+ set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY);
+ set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY);
#ifdef CONFIG_VMAP_STACK
cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
NULL, free_vm_stack_cache);
#endif
+ scs_init();
+
lockdep_init_task(&init_task);
uprobes_init();
}
@@ -859,8 +959,6 @@ void set_task_stack_end_magic(struct task_struct *tsk)
static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
struct task_struct *tsk;
- unsigned long *stack;
- struct vm_struct *stack_vm_area __maybe_unused;
int err;
if (node == NUMA_NO_NODE)
@@ -869,30 +967,20 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
if (!tsk)
return NULL;
- stack = alloc_thread_stack_node(tsk, node);
- if (!stack)
+ err = arch_dup_task_struct(tsk, orig);
+ if (err)
goto free_tsk;
- if (memcg_charge_kernel_stack(tsk))
- goto free_stack;
-
- stack_vm_area = task_stack_vm_area(tsk);
-
- err = arch_dup_task_struct(tsk, orig);
+ err = alloc_thread_stack_node(tsk, node);
+ if (err)
+ goto free_tsk;
- /*
- * arch_dup_task_struct() clobbers the stack-related fields. Make
- * sure they're properly initialized before using any stack-related
- * functions again.
- */
- tsk->stack = stack;
-#ifdef CONFIG_VMAP_STACK
- tsk->stack_vm_area = stack_vm_area;
-#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
refcount_set(&tsk->stack_refcount, 1);
#endif
+ account_kernel_stack(tsk, 1);
+ err = scs_prepare(tsk, node);
if (err)
goto free_stack;
@@ -910,12 +998,14 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
clear_user_return_notifier(tsk);
clear_tsk_need_resched(tsk);
set_task_stack_end_magic(tsk);
+ clear_syscall_work_syscall_user_dispatch(tsk);
#ifdef CONFIG_STACKPROTECTOR
tsk->stack_canary = get_random_canary();
#endif
if (orig->cpus_ptr == &orig->cpus_mask)
tsk->cpus_ptr = &tsk->cpus_mask;
+ dup_user_cpus_ptr(tsk, orig, node);
/*
* One for the user space visible state that goes away when reaped.
@@ -930,10 +1020,11 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->splice_pipe = NULL;
tsk->task_frag.page = NULL;
tsk->wake_q.next = NULL;
-
- account_kernel_stack(tsk, 1);
+ tsk->worker_private = NULL;
kcov_task_init(tsk);
+ kmsan_task_create(tsk);
+ kmap_local_fork(tsk);
#ifdef CONFIG_FAULT_INJECTION
tsk->fail_nth = 0;
@@ -944,12 +1035,22 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->use_memdelay = 0;
#endif
+#ifdef CONFIG_IOMMU_SVA
+ tsk->pasid_activated = 0;
+#endif
+
#ifdef CONFIG_MEMCG
tsk->active_memcg = NULL;
#endif
+
+#ifdef CONFIG_CPU_SUP_INTEL
+ tsk->reported_split_lock = 0;
+#endif
+
return tsk;
free_stack:
+ exit_task_stack_account(tsk);
free_thread_stack(tsk);
free_tsk:
free_task_struct(tsk);
@@ -1006,14 +1107,13 @@ static void mm_init_uprobes_state(struct mm_struct *mm)
static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
struct user_namespace *user_ns)
{
- mm->mmap = NULL;
- mm->mm_rb = RB_ROOT;
- mm->vmacache_seqnum = 0;
+ mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
+ mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);
- init_rwsem(&mm->mmap_sem);
+ seqcount_init(&mm->write_protect_seq);
+ mmap_init_lock(mm);
INIT_LIST_HEAD(&mm->mmlist);
- mm->core_state = NULL;
mm_pgtables_bytes_init(mm);
mm->map_count = 0;
mm->locked_vm = 0;
@@ -1024,6 +1124,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm_init_cpumask(mm);
mm_init_aio(mm);
mm_init_owner(mm, p);
+ mm_pasid_init(mm);
RCU_INIT_POINTER(mm->exe_file, NULL);
mmu_notifier_subscriptions_init(mm);
init_tlb_flush_pending(mm);
@@ -1031,6 +1132,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm->pmd_huge_pte = NULL;
#endif
mm_init_uprobes_state(mm);
+ hugetlb_count_init(mm);
if (current->mm) {
mm->flags = current->mm->flags & MMF_INIT_MASK;
@@ -1047,6 +1149,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
goto fail_nocontext;
mm->user_ns = get_user_ns(user_ns);
+ lru_gen_init_mm(mm);
return mm;
fail_nocontext:
@@ -1089,6 +1192,7 @@ static inline void __mmput(struct mm_struct *mm)
}
if (mm->binfmt)
module_put(mm->binfmt->module);
+ lru_gen_del_mm(mm);
mmdrop(mm);
}
@@ -1120,6 +1224,7 @@ void mmput_async(struct mm_struct *mm)
schedule_work(&mm->async_put_work);
}
}
+EXPORT_SYMBOL_GPL(mmput_async);
#endif
/**
@@ -1129,11 +1234,11 @@ void mmput_async(struct mm_struct *mm)
*
* Main users are mmput() and sys_execve(). Callers prevent concurrent
* invocations: in mmput() nobody alive left, in execve task is single
- * threaded. sys_prctl(PR_SET_MM_MAP/EXE_FILE) also needs to set the
- * mm->exe_file, but does so without using set_mm_exe_file() in order
- * to do avoid the need for any locks.
+ * threaded.
+ *
+ * Can only fail if new_exe_file != NULL.
*/
-void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
+int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
{
struct file *old_exe_file;
@@ -1144,11 +1249,76 @@ void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
*/
old_exe_file = rcu_dereference_raw(mm->exe_file);
- if (new_exe_file)
+ if (new_exe_file) {
+ /*
+ * We expect the caller (i.e., sys_execve) to already denied
+ * write access, so this is unlikely to fail.
+ */
+ if (unlikely(deny_write_access(new_exe_file)))
+ return -EACCES;
get_file(new_exe_file);
+ }
rcu_assign_pointer(mm->exe_file, new_exe_file);
- if (old_exe_file)
+ if (old_exe_file) {
+ allow_write_access(old_exe_file);
fput(old_exe_file);
+ }
+ return 0;
+}
+
+/**
+ * replace_mm_exe_file - replace a reference to the mm's executable file
+ *
+ * This changes mm's executable file (shown as symlink /proc/[pid]/exe),
+ * dealing with concurrent invocation and without grabbing the mmap lock in
+ * write mode.
+ *
+ * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE).
+ */
+int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
+{
+ struct vm_area_struct *vma;
+ struct file *old_exe_file;
+ int ret = 0;
+
+ /* Forbid mm->exe_file change if old file still mapped. */
+ old_exe_file = get_mm_exe_file(mm);
+ if (old_exe_file) {
+ VMA_ITERATOR(vmi, mm, 0);
+ mmap_read_lock(mm);
+ for_each_vma(vmi, vma) {
+ if (!vma->vm_file)
+ continue;
+ if (path_equal(&vma->vm_file->f_path,
+ &old_exe_file->f_path)) {
+ ret = -EBUSY;
+ break;
+ }
+ }
+ mmap_read_unlock(mm);
+ fput(old_exe_file);
+ if (ret)
+ return ret;
+ }
+
+ /* set the new file, lockless */
+ ret = deny_write_access(new_exe_file);
+ if (ret)
+ return -EACCES;
+ get_file(new_exe_file);
+
+ old_exe_file = xchg(&mm->exe_file, new_exe_file);
+ if (old_exe_file) {
+ /*
+ * Don't race with dup_mmap() getting the file and disallowing
+ * write access while someone might open the file writable.
+ */
+ mmap_read_lock(mm);
+ allow_write_access(old_exe_file);
+ fput(old_exe_file);
+ mmap_read_unlock(mm);
+ }
+ return 0;
}
/**
@@ -1168,7 +1338,6 @@ struct file *get_mm_exe_file(struct mm_struct *mm)
rcu_read_unlock();
return exe_file;
}
-EXPORT_SYMBOL(get_mm_exe_file);
/**
* get_task_exe_file - acquire a reference to the task's executable file
@@ -1191,7 +1360,6 @@ struct file *get_task_exe_file(struct task_struct *task)
task_unlock(task);
return exe_file;
}
-EXPORT_SYMBOL(get_task_exe_file);
/**
* get_task_mm - acquire a reference to the task's mm
@@ -1224,7 +1392,7 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
struct mm_struct *mm;
int err;
- err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ err = down_read_killable(&task->signal->exec_update_lock);
if (err)
return ERR_PTR(err);
@@ -1234,7 +1402,7 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
mmput(mm);
mm = ERR_PTR(-EACCES);
}
- mutex_unlock(&task->signal->cred_guard_mutex);
+ up_read(&task->signal->exec_update_lock);
return mm;
}
@@ -1255,13 +1423,12 @@ static void complete_vfork_done(struct task_struct *tsk)
static int wait_for_vfork_done(struct task_struct *child,
struct completion *vfork)
{
+ unsigned int state = TASK_UNINTERRUPTIBLE|TASK_KILLABLE|TASK_FREEZABLE;
int killed;
- freezer_do_not_count();
cgroup_enter_frozen();
- killed = wait_for_completion_killable(vfork);
+ killed = wait_for_completion_state(vfork, state);
cgroup_leave_frozen(false);
- freezer_count();
if (killed) {
task_lock(child);
@@ -1299,8 +1466,7 @@ static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
* purposes.
*/
if (tsk->clear_child_tid) {
- if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) &&
- atomic_read(&mm->mm_users) > 1) {
+ if (atomic_read(&mm->mm_users) > 1) {
/*
* We don't check the error code - if userspace has
* not set up a proper pointer then tough luck.
@@ -1382,7 +1548,6 @@ fail_nomem:
static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
{
struct mm_struct *mm, *oldmm;
- int retval;
tsk->min_flt = tsk->maj_flt = 0;
tsk->nvcsw = tsk->nivcsw = 0;
@@ -1403,27 +1568,18 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
if (!oldmm)
return 0;
- /* initialize the new vmacache entries */
- vmacache_flush(tsk);
-
if (clone_flags & CLONE_VM) {
mmget(oldmm);
mm = oldmm;
- goto good_mm;
+ } else {
+ mm = dup_mm(tsk, current->mm);
+ if (!mm)
+ return -ENOMEM;
}
- retval = -ENOMEM;
- mm = dup_mm(tsk, current->mm);
- if (!mm)
- goto fail_nomem;
-
-good_mm:
tsk->mm = mm;
tsk->active_mm = mm;
return 0;
-
-fail_nomem:
- return retval;
}
static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
@@ -1463,7 +1619,7 @@ static int copy_files(unsigned long clone_flags, struct task_struct *tsk)
goto out;
}
- newf = dup_fd(oldf, &error);
+ newf = dup_fd(oldf, NR_OPEN_MAX, &error);
if (!newf)
goto out;
@@ -1473,32 +1629,6 @@ out:
return error;
}
-static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
-{
-#ifdef CONFIG_BLOCK
- struct io_context *ioc = current->io_context;
- struct io_context *new_ioc;
-
- if (!ioc)
- return 0;
- /*
- * Share io context with parent, if CLONE_IO is set
- */
- if (clone_flags & CLONE_IO) {
- ioc_task_link(ioc);
- tsk->io_context = ioc;
- } else if (ioprio_valid(ioc->ioprio)) {
- new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
- if (unlikely(!new_ioc))
- return -ENOMEM;
-
- new_ioc->ioprio = ioc->ioprio;
- put_io_context(new_ioc);
- }
-#endif
- return 0;
-}
-
static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
{
struct sighand_struct *sig;
@@ -1561,6 +1691,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
return -ENOMEM;
sig->nr_threads = 1;
+ sig->quick_threads = 1;
atomic_set(&sig->live, 1);
refcount_set(&sig->sigcnt, 1);
@@ -1594,6 +1725,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->oom_score_adj_min = current->signal->oom_score_adj_min;
mutex_init(&sig->cred_guard_mutex);
+ init_rwsem(&sig->exec_update_lock);
return 0;
}
@@ -1627,7 +1759,7 @@ static void copy_seccomp(struct task_struct *p)
* to manually enable the seccomp thread flag here.
*/
if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
- set_tsk_thread_flag(p, TIF_SECCOMP);
+ set_task_syscall_work(p, SECCOMP);
#endif
}
@@ -1652,9 +1784,8 @@ static inline void init_task_pid_links(struct task_struct *task)
{
enum pid_type type;
- for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
+ for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type)
INIT_HLIST_NODE(&task->pid_links[type]);
- }
}
static inline void
@@ -1679,6 +1810,12 @@ static inline void rcu_copy_process(struct task_struct *p)
INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
p->rcu_tasks_idle_cpu = -1;
#endif /* #ifdef CONFIG_TASKS_RCU */
+#ifdef CONFIG_TASKS_TRACE_RCU
+ p->trc_reader_nesting = 0;
+ p->trc_reader_special.s = 0;
+ INIT_LIST_HEAD(&p->trc_holdout_list);
+ INIT_LIST_HEAD(&p->trc_blkd_node);
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
}
struct pid *pidfd_pid(const struct file *file)
@@ -1724,7 +1861,7 @@ static int pidfd_release(struct inode *inode, struct file *file)
* /proc/<pid>/status where Pid and NSpid are always shown relative to
* the pid namespace of the procfs instance. The difference becomes
* obvious when sending around a pidfd between pid namespaces from a
- * different branch of the tree, i.e. where no ancestoral relation is
+ * different branch of the tree, i.e. where no ancestral relation is
* present between the pid namespaces:
* - create two new pid namespaces ns1 and ns2 in the initial pid
* namespace (also take care to create new mount namespaces in the
@@ -1741,7 +1878,7 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f)
pid_t nr = -1;
if (likely(pid_has_task(pid, PIDTYPE_PID))) {
- ns = proc_pid_ns(file_inode(m->file));
+ ns = proc_pid_ns(file_inode(m->file)->i_sb);
nr = pid_nr_ns(pid, ns);
}
@@ -1770,22 +1907,18 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f)
*/
static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts)
{
- struct task_struct *task;
struct pid *pid = file->private_data;
__poll_t poll_flags = 0;
poll_wait(file, &pid->wait_pidfd, pts);
- rcu_read_lock();
- task = pid_task(pid, PIDTYPE_PID);
/*
* Inform pollers only when the whole thread group exits.
* If the thread group leader exits before all other threads in the
* group, then poll(2) should block, similar to the wait(2) family.
*/
- if (!task || (task->exit_state && thread_group_empty(task)))
+ if (thread_group_exited(pid))
poll_flags = EPOLLIN | EPOLLRDNORM;
- rcu_read_unlock();
return poll_flags;
}
@@ -1813,6 +1946,37 @@ static __always_inline void delayed_free_task(struct task_struct *tsk)
free_task(tsk);
}
+static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk)
+{
+ /* Skip if kernel thread */
+ if (!tsk->mm)
+ return;
+
+ /* Skip if spawning a thread or using vfork */
+ if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM)
+ return;
+
+ /* We need to synchronize with __set_oom_adj */
+ mutex_lock(&oom_adj_mutex);
+ set_bit(MMF_MULTIPROCESS, &tsk->mm->flags);
+ /* Update the values in case they were changed after copy_signal */
+ tsk->signal->oom_score_adj = current->signal->oom_score_adj;
+ tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min;
+ mutex_unlock(&oom_adj_mutex);
+}
+
+#ifdef CONFIG_RV
+static void rv_task_fork(struct task_struct *p)
+{
+ int i;
+
+ for (i = 0; i < RV_PER_TASK_MONITORS; i++)
+ p->rv[i].da_mon.monitoring = false;
+}
+#else
+#define rv_task_fork(p) do {} while (0)
+#endif
+
/*
* This creates a new process as a copy of the old one,
* but does not actually start it yet.
@@ -1831,7 +1995,7 @@ static __latent_entropy struct task_struct *copy_process(
struct task_struct *p;
struct multiprocess_signals delayed;
struct file *pidfile = NULL;
- u64 clone_flags = args->flags;
+ const u64 clone_flags = args->flags;
struct nsproxy *nsp = current->nsproxy;
/*
@@ -1913,20 +2077,25 @@ static __latent_entropy struct task_struct *copy_process(
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
retval = -ERESTARTNOINTR;
- if (signal_pending(current))
+ if (task_sigpending(current))
goto fork_out;
retval = -ENOMEM;
p = dup_task_struct(current, node);
if (!p)
goto fork_out;
+ p->flags &= ~PF_KTHREAD;
+ if (args->kthread)
+ p->flags |= PF_KTHREAD;
+ if (args->io_thread) {
+ /*
+ * Mark us an IO worker, and block any signal that isn't
+ * fatal or STOP
+ */
+ p->flags |= PF_IO_WORKER;
+ siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
+ }
- /*
- * This _must_ happen before we call free_task(), i.e. before we jump
- * to any of the bad_fork_* labels. This is to avoid freeing
- * p->set_child_tid which is (ab)used as a kthread's data pointer for
- * kernel threads (PF_KTHREAD).
- */
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
/*
* Clear TID on mm_release()?
@@ -1937,34 +2106,33 @@ static __latent_entropy struct task_struct *copy_process(
rt_mutex_init_task(p);
+ lockdep_assert_irqs_enabled();
#ifdef CONFIG_PROVE_LOCKING
- DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
+ retval = copy_creds(p, clone_flags);
+ if (retval < 0)
+ goto bad_fork_free;
+
retval = -EAGAIN;
- if (atomic_read(&p->real_cred->user->processes) >=
- task_rlimit(p, RLIMIT_NPROC)) {
+ if (is_rlimit_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
if (p->real_cred->user != INIT_USER &&
!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
- goto bad_fork_free;
+ goto bad_fork_cleanup_count;
}
current->flags &= ~PF_NPROC_EXCEEDED;
- retval = copy_creds(p, clone_flags);
- if (retval < 0)
- goto bad_fork_free;
-
/*
* If multiple threads are within copy_process(), then this check
* triggers too late. This doesn't hurt, the check is only there
* to stop root fork bombs.
*/
retval = -EAGAIN;
- if (nr_threads >= max_threads)
+ if (data_race(nr_threads >= max_threads))
goto bad_fork_cleanup_count;
delayacct_tsk_init(p); /* Must remain after dup_task_struct() */
- p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE);
+ p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY);
p->flags |= PF_FORKNOEXEC;
INIT_LIST_HEAD(&p->children);
INIT_LIST_HEAD(&p->sibling);
@@ -1986,6 +2154,10 @@ static __latent_entropy struct task_struct *copy_process(
p->vtime.state = VTIME_INACTIVE;
#endif
+#ifdef CONFIG_IO_URING
+ p->io_uring = NULL;
+#endif
+
#if defined(SPLIT_RSS_COUNTING)
memset(&p->rss_stat, 0, sizeof(p->rss_stat));
#endif
@@ -2004,33 +2176,29 @@ static __latent_entropy struct task_struct *copy_process(
p->io_context = NULL;
audit_set_context(p, NULL);
cgroup_fork(p);
+ if (args->kthread) {
+ if (!set_kthread_struct(p))
+ goto bad_fork_cleanup_delayacct;
+ }
#ifdef CONFIG_NUMA
p->mempolicy = mpol_dup(p->mempolicy);
if (IS_ERR(p->mempolicy)) {
retval = PTR_ERR(p->mempolicy);
p->mempolicy = NULL;
- goto bad_fork_cleanup_threadgroup_lock;
+ goto bad_fork_cleanup_delayacct;
}
#endif
#ifdef CONFIG_CPUSETS
p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
- seqcount_init(&p->mems_allowed_seq);
+ seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
- p->irq_events = 0;
- p->hardirqs_enabled = 0;
- p->hardirq_enable_ip = 0;
- p->hardirq_enable_event = 0;
- p->hardirq_disable_ip = _THIS_IP_;
- p->hardirq_disable_event = 0;
- p->softirqs_enabled = 1;
- p->softirq_enable_ip = _THIS_IP_;
- p->softirq_enable_event = 0;
- p->softirq_disable_ip = 0;
- p->softirq_disable_event = 0;
- p->hardirq_context = 0;
- p->softirq_context = 0;
+ memset(&p->irqtrace, 0, sizeof(p->irqtrace));
+ p->irqtrace.hardirq_disable_ip = _THIS_IP_;
+ p->irqtrace.softirq_enable_ip = _THIS_IP_;
+ p->softirqs_enabled = 1;
+ p->softirq_context = 0;
#endif
p->pagefault_disabled = 0;
@@ -2046,13 +2214,17 @@ static __latent_entropy struct task_struct *copy_process(
p->sequential_io = 0;
p->sequential_io_avg = 0;
#endif
+#ifdef CONFIG_BPF_SYSCALL
+ RCU_INIT_POINTER(p->bpf_storage, NULL);
+ p->bpf_ctx = NULL;
+#endif
/* Perform scheduler related setup. Assign this task to a CPU. */
retval = sched_fork(clone_flags, p);
if (retval)
goto bad_fork_cleanup_policy;
- retval = perf_event_init_task(p);
+ retval = perf_event_init_task(p, clone_flags);
if (retval)
goto bad_fork_cleanup_policy;
retval = audit_alloc(p);
@@ -2087,8 +2259,7 @@ static __latent_entropy struct task_struct *copy_process(
retval = copy_io(clone_flags, p);
if (retval)
goto bad_fork_cleanup_namespaces;
- retval = copy_thread_tls(clone_flags, args->stack, args->stack_size, p,
- args->tls);
+ retval = copy_thread(p, args);
if (retval)
goto bad_fork_cleanup_io;
@@ -2145,23 +2316,18 @@ static __latent_entropy struct task_struct *copy_process(
* child regardless of CLONE_PTRACE.
*/
user_disable_single_step(p);
- clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
-#ifdef TIF_SYSCALL_EMU
- clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
+ clear_task_syscall_work(p, SYSCALL_TRACE);
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
+ clear_task_syscall_work(p, SYSCALL_EMU);
#endif
clear_tsk_latency_tracing(p);
/* ok, now we should be set up.. */
p->pid = pid_nr(pid);
if (clone_flags & CLONE_THREAD) {
- p->exit_signal = -1;
p->group_leader = current->group_leader;
p->tgid = current->tgid;
} else {
- if (clone_flags & CLONE_PARENT)
- p->exit_signal = current->group_leader->exit_signal;
- else
- p->exit_signal = args->exit_signal;
p->group_leader = p;
p->tgid = p->pid;
}
@@ -2173,17 +2339,35 @@ static __latent_entropy struct task_struct *copy_process(
p->pdeath_signal = 0;
INIT_LIST_HEAD(&p->thread_group);
p->task_works = NULL;
+ clear_posix_cputimers_work(p);
+
+#ifdef CONFIG_KRETPROBES
+ p->kretprobe_instances.first = NULL;
+#endif
+#ifdef CONFIG_RETHOOK
+ p->rethooks.first = NULL;
+#endif
- cgroup_threadgroup_change_begin(current);
/*
* Ensure that the cgroup subsystem policies allow the new process to be
- * forked. It should be noted the the new process's css_set can be changed
+ * forked. It should be noted that the new process's css_set can be changed
* between here and cgroup_post_fork() if an organisation operation is in
* progress.
*/
- retval = cgroup_can_fork(p);
+ retval = cgroup_can_fork(p, args);
if (retval)
- goto bad_fork_cgroup_threadgroup_change_end;
+ goto bad_fork_put_pidfd;
+
+ /*
+ * Now that the cgroups are pinned, re-clone the parent cgroup and put
+ * the new task on the correct runqueue. All this *before* the task
+ * becomes visible.
+ *
+ * This isn't part of ->can_fork() because while the re-cloning is
+ * cgroup specific, it unconditionally needs to place the task on a
+ * runqueue.
+ */
+ sched_cgroup_fork(p, args);
/*
* From this point on we must avoid any synchronous user-space
@@ -2206,13 +2390,20 @@ static __latent_entropy struct task_struct *copy_process(
if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
p->real_parent = current->real_parent;
p->parent_exec_id = current->parent_exec_id;
+ if (clone_flags & CLONE_THREAD)
+ p->exit_signal = -1;
+ else
+ p->exit_signal = current->group_leader->exit_signal;
} else {
p->real_parent = current;
p->parent_exec_id = current->self_exec_id;
+ p->exit_signal = args->exit_signal;
}
klp_copy_process(p);
+ sched_core_fork(p);
+
spin_lock(&current->sighand->siglock);
/*
@@ -2221,6 +2412,8 @@ static __latent_entropy struct task_struct *copy_process(
*/
copy_seccomp(p);
+ rv_task_fork(p);
+
rseq_fork(p, clone_flags);
/* Don't start children in a dying pid namespace */
@@ -2235,10 +2428,6 @@ static __latent_entropy struct task_struct *copy_process(
goto bad_fork_cancel_cgroup;
}
- /* past the last point of failure */
- if (pidfile)
- fd_install(pidfd, pidfile);
-
init_task_pid_links(p);
if (likely(p->pid)) {
ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
@@ -2270,6 +2459,7 @@ static __latent_entropy struct task_struct *copy_process(
__this_cpu_inc(process_counts);
} else {
current->signal->nr_threads++;
+ current->signal->quick_threads++;
atomic_inc(&current->signal->live);
refcount_inc(&current->signal->sigcnt);
task_join_group_stop(p);
@@ -2287,22 +2477,26 @@ static __latent_entropy struct task_struct *copy_process(
syscall_tracepoint_update(p);
write_unlock_irq(&tasklist_lock);
+ if (pidfile)
+ fd_install(pidfd, pidfile);
+
proc_fork_connector(p);
- cgroup_post_fork(p);
- cgroup_threadgroup_change_end(current);
+ sched_post_fork(p);
+ cgroup_post_fork(p, args);
perf_event_fork(p);
trace_task_newtask(p, clone_flags);
uprobe_copy_process(p, clone_flags);
+ copy_oom_score_adj(clone_flags, p);
+
return p;
bad_fork_cancel_cgroup:
+ sched_core_free(p);
spin_unlock(&current->sighand->siglock);
write_unlock_irq(&tasklist_lock);
- cgroup_cancel_fork(p);
-bad_fork_cgroup_threadgroup_change_end:
- cgroup_threadgroup_change_end(current);
+ cgroup_cancel_fork(p, args);
bad_fork_put_pidfd:
if (clone_flags & CLONE_PIDFD) {
fput(pidfile);
@@ -2344,14 +2538,15 @@ bad_fork_cleanup_policy:
lockdep_free_task(p);
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
-bad_fork_cleanup_threadgroup_lock:
#endif
+bad_fork_cleanup_delayacct:
delayacct_tsk_free(p);
bad_fork_cleanup_count:
- atomic_dec(&p->cred->user->processes);
+ dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
exit_creds(p);
bad_fork_free:
- p->state = TASK_DEAD;
+ WRITE_ONCE(p->__state, TASK_DEAD);
+ exit_task_stack_account(p);
put_task_stack(p);
delayed_free_task(p);
fork_out:
@@ -2371,11 +2566,21 @@ static inline void init_idle_pids(struct task_struct *idle)
}
}
-struct task_struct *fork_idle(int cpu)
+static int idle_dummy(void *dummy)
+{
+ /* This function is never called */
+ return 0;
+}
+
+struct task_struct * __init fork_idle(int cpu)
{
struct task_struct *task;
struct kernel_clone_args args = {
- .flags = CLONE_VM,
+ .flags = CLONE_VM,
+ .fn = &idle_dummy,
+ .fn_arg = NULL,
+ .kthread = 1,
+ .idle = 1,
};
task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args);
@@ -2393,6 +2598,28 @@ struct mm_struct *copy_init_mm(void)
}
/*
+ * This is like kernel_clone(), but shaved down and tailored to just
+ * creating io_uring workers. It returns a created task, or an error pointer.
+ * The returned task is inactive, and the caller must fire it up through
+ * wake_up_new_task(p). All signals are blocked in the created task.
+ */
+struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
+{
+ unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
+ CLONE_IO;
+ struct kernel_clone_args args = {
+ .flags = ((lower_32_bits(flags) | CLONE_VM |
+ CLONE_UNTRACED) & ~CSIGNAL),
+ .exit_signal = (lower_32_bits(flags) & CSIGNAL),
+ .fn = fn,
+ .fn_arg = arg,
+ .io_thread = 1,
+ };
+
+ return copy_process(NULL, 0, node, &args);
+}
+
+/*
* Ok, this is the main fork-routine.
*
* It copies the process, and if successful kick-starts
@@ -2400,14 +2627,28 @@ struct mm_struct *copy_init_mm(void)
*
* args->exit_signal is expected to be checked for sanity by the caller.
*/
-long _do_fork(struct kernel_clone_args *args)
+pid_t kernel_clone(struct kernel_clone_args *args)
{
u64 clone_flags = args->flags;
struct completion vfork;
struct pid *pid;
struct task_struct *p;
int trace = 0;
- long nr;
+ pid_t nr;
+
+ /*
+ * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument
+ * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are
+ * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate
+ * field in struct clone_args and it still doesn't make sense to have
+ * them both point at the same memory location. Performing this check
+ * here has the advantage that we don't need to have a separate helper
+ * to check for legacy clone().
+ */
+ if ((args->flags & CLONE_PIDFD) &&
+ (args->flags & CLONE_PARENT_SETTID) &&
+ (args->pidfd == args->parent_tid))
+ return -EINVAL;
/*
* Determine whether and which event to report to ptracer. When
@@ -2451,6 +2692,13 @@ long _do_fork(struct kernel_clone_args *args)
get_task_struct(p);
}
+ if (IS_ENABLED(CONFIG_LRU_GEN) && !(clone_flags & CLONE_VM)) {
+ /* lock the task to synchronize with memcg migration */
+ task_lock(p);
+ lru_gen_add_mm(p->mm);
+ task_unlock(p);
+ }
+
wake_up_new_task(p);
/* forking complete and child started to run, tell ptracer */
@@ -2466,55 +2714,37 @@ long _do_fork(struct kernel_clone_args *args)
return nr;
}
-bool legacy_clone_args_valid(const struct kernel_clone_args *kargs)
-{
- /* clone(CLONE_PIDFD) uses parent_tidptr to return a pidfd */
- if ((kargs->flags & CLONE_PIDFD) &&
- (kargs->flags & CLONE_PARENT_SETTID))
- return false;
-
- return true;
-}
-
-#ifndef CONFIG_HAVE_COPY_THREAD_TLS
-/* For compatibility with architectures that call do_fork directly rather than
- * using the syscall entry points below. */
-long do_fork(unsigned long clone_flags,
- unsigned long stack_start,
- unsigned long stack_size,
- int __user *parent_tidptr,
- int __user *child_tidptr)
+/*
+ * Create a kernel thread.
+ */
+pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct kernel_clone_args args = {
- .flags = (clone_flags & ~CSIGNAL),
- .pidfd = parent_tidptr,
- .child_tid = child_tidptr,
- .parent_tid = parent_tidptr,
- .exit_signal = (clone_flags & CSIGNAL),
- .stack = stack_start,
- .stack_size = stack_size,
+ .flags = ((lower_32_bits(flags) | CLONE_VM |
+ CLONE_UNTRACED) & ~CSIGNAL),
+ .exit_signal = (lower_32_bits(flags) & CSIGNAL),
+ .fn = fn,
+ .fn_arg = arg,
+ .kthread = 1,
};
- if (!legacy_clone_args_valid(&args))
- return -EINVAL;
-
- return _do_fork(&args);
+ return kernel_clone(&args);
}
-#endif
/*
- * Create a kernel thread.
+ * Create a user mode thread.
*/
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct kernel_clone_args args = {
- .flags = ((flags | CLONE_VM | CLONE_UNTRACED) & ~CSIGNAL),
- .exit_signal = (flags & CSIGNAL),
- .stack = (unsigned long)fn,
- .stack_size = (unsigned long)arg,
+ .flags = ((lower_32_bits(flags) | CLONE_VM |
+ CLONE_UNTRACED) & ~CSIGNAL),
+ .exit_signal = (lower_32_bits(flags) & CSIGNAL),
+ .fn = fn,
+ .fn_arg = arg,
};
- return _do_fork(&args);
+ return kernel_clone(&args);
}
#ifdef __ARCH_WANT_SYS_FORK
@@ -2525,7 +2755,7 @@ SYSCALL_DEFINE0(fork)
.exit_signal = SIGCHLD,
};
- return _do_fork(&args);
+ return kernel_clone(&args);
#else
/* can not support in nommu mode */
return -EINVAL;
@@ -2541,7 +2771,7 @@ SYSCALL_DEFINE0(vfork)
.exit_signal = SIGCHLD,
};
- return _do_fork(&args);
+ return kernel_clone(&args);
}
#endif
@@ -2570,33 +2800,21 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
#endif
{
struct kernel_clone_args args = {
- .flags = (clone_flags & ~CSIGNAL),
+ .flags = (lower_32_bits(clone_flags) & ~CSIGNAL),
.pidfd = parent_tidptr,
.child_tid = child_tidptr,
.parent_tid = parent_tidptr,
- .exit_signal = (clone_flags & CSIGNAL),
+ .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL),
.stack = newsp,
.tls = tls,
};
- if (!legacy_clone_args_valid(&args))
- return -EINVAL;
-
- return _do_fork(&args);
+ return kernel_clone(&args);
}
#endif
#ifdef __ARCH_WANT_SYS_CLONE3
-/*
- * copy_thread implementations handle CLONE_SETTLS by reading the TLS value from
- * the registers containing the syscall arguments for clone. This doesn't work
- * with clone3 since the TLS value is passed in clone_args instead.
- */
-#ifndef CONFIG_HAVE_COPY_THREAD_TLS
-#error clone3 requires copy_thread_tls support in arch
-#endif
-
noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
struct clone_args __user *uargs,
size_t usize)
@@ -2605,6 +2823,14 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
struct clone_args args;
pid_t *kset_tid = kargs->set_tid;
+ BUILD_BUG_ON(offsetofend(struct clone_args, tls) !=
+ CLONE_ARGS_SIZE_VER0);
+ BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) !=
+ CLONE_ARGS_SIZE_VER1);
+ BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) !=
+ CLONE_ARGS_SIZE_VER2);
+ BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2);
+
if (unlikely(usize > PAGE_SIZE))
return -E2BIG;
if (unlikely(usize < CLONE_ARGS_SIZE_VER0))
@@ -2631,6 +2857,10 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
!valid_signal(args.exit_signal)))
return -EINVAL;
+ if ((args.flags & CLONE_INTO_CGROUP) &&
+ (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2))
+ return -EINVAL;
+
*kargs = (struct kernel_clone_args){
.flags = args.flags,
.pidfd = u64_to_user_ptr(args.pidfd),
@@ -2641,6 +2871,7 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
.stack_size = args.stack_size,
.tls = args.tls,
.set_tid_size = args.set_tid_size,
+ .cgroup = args.cgroup,
};
if (args.set_tid &&
@@ -2684,12 +2915,13 @@ static inline bool clone3_stack_valid(struct kernel_clone_args *kargs)
static bool clone3_args_valid(struct kernel_clone_args *kargs)
{
/* Verify that no unknown flags are passed along. */
- if (kargs->flags & ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND))
+ if (kargs->flags &
+ ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP))
return false;
/*
- * - make the CLONE_DETACHED bit reuseable for clone3
- * - make the CSIGNAL bits reuseable for clone3
+ * - make the CLONE_DETACHED bit reusable for clone3
+ * - make the CSIGNAL bits reusable for clone3
*/
if (kargs->flags & (CLONE_DETACHED | CSIGNAL))
return false;
@@ -2735,7 +2967,7 @@ SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
if (!clone3_args_valid(&kargs))
return -EINVAL;
- return _do_fork(&kargs);
+ return kernel_clone(&kargs);
}
#endif
@@ -2879,14 +3111,15 @@ static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
/*
* Unshare file descriptor table if it is being shared
*/
-static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
+int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
+ struct files_struct **new_fdp)
{
struct files_struct *fd = current->files;
int error = 0;
if ((unshare_flags & CLONE_FILES) &&
(fd && atomic_read(&fd->count) > 1)) {
- *new_fdp = dup_fd(fd, &error);
+ *new_fdp = dup_fd(fd, max_fds, &error);
if (!*new_fdp)
return error;
}
@@ -2897,7 +3130,7 @@ static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp
/*
* unshare allows a process to 'unshare' part of the process
* context which was originally shared using clone. copy_*
- * functions used by do_fork() cannot be used here directly
+ * functions used by kernel_clone() cannot be used here directly
* because they modify an inactive task_struct that is being
* constructed. Here we are modifying the current, active,
* task_struct.
@@ -2905,7 +3138,7 @@ static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp
int ksys_unshare(unsigned long unshare_flags)
{
struct fs_struct *fs, *new_fs = NULL;
- struct files_struct *fd, *new_fd = NULL;
+ struct files_struct *new_fd = NULL;
struct cred *new_cred = NULL;
struct nsproxy *new_nsproxy = NULL;
int do_sysvsem = 0;
@@ -2946,7 +3179,7 @@ int ksys_unshare(unsigned long unshare_flags)
err = unshare_fs(unshare_flags, &new_fs);
if (err)
goto bad_unshare_out;
- err = unshare_fd(unshare_flags, &new_fd);
+ err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd);
if (err)
goto bad_unshare_cleanup_fs;
err = unshare_userns(unshare_flags, &new_cred);
@@ -2957,6 +3190,12 @@ int ksys_unshare(unsigned long unshare_flags)
if (err)
goto bad_unshare_cleanup_cred;
+ if (new_cred) {
+ err = set_cred_ucounts(new_cred);
+ if (err)
+ goto bad_unshare_cleanup_cred;
+ }
+
if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
if (do_sysvsem) {
/*
@@ -2986,11 +3225,8 @@ int ksys_unshare(unsigned long unshare_flags)
spin_unlock(&fs->lock);
}
- if (new_fd) {
- fd = current->files;
- current->files = new_fd;
- new_fd = fd;
- }
+ if (new_fd)
+ swap(current->files, new_fd);
task_unlock(current);
@@ -3029,26 +3265,26 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
* the exec layer of the kernel.
*/
-int unshare_files(struct files_struct **displaced)
+int unshare_files(void)
{
struct task_struct *task = current;
- struct files_struct *copy = NULL;
+ struct files_struct *old, *copy = NULL;
int error;
- error = unshare_fd(CLONE_FILES, &copy);
- if (error || !copy) {
- *displaced = NULL;
+ error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, &copy);
+ if (error || !copy)
return error;
- }
- *displaced = task->files;
+
+ old = task->files;
task_lock(task);
task->files = copy;
task_unlock(task);
+ put_files_struct(old);
return 0;
}
int sysctl_max_threads(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
+ void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table t;
int ret;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.