diff options
Diffstat (limited to 'kernel/trace/fgraph.c')
| -rw-r--r-- | kernel/trace/fgraph.c | 56 |
1 files changed, 33 insertions, 23 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 1af321dec0f1..218cd95bf8e4 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -7,6 +7,7 @@ * * Highly modified by Steven Rostedt (VMware). */ +#include <linux/jump_label.h> #include <linux/suspend.h> #include <linux/ftrace.h> #include <linux/slab.h> @@ -23,26 +24,34 @@ #define ASSIGN_OPS_HASH(opsname, val) #endif -static bool kill_ftrace_graph; +DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph); int ftrace_graph_active; /* Both enabled by default (can be cleared by function_graph tracer flags */ static bool fgraph_sleep_time = true; -/** - * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called - * - * ftrace_graph_stop() is called when a severe error is detected in - * the function graph tracing. This function is called by the critical - * paths of function graph to keep those paths from doing any more harm. +#ifdef CONFIG_DYNAMIC_FTRACE +/* + * archs can override this function if they must do something + * to enable hook for graph tracer. + */ +int __weak ftrace_enable_ftrace_graph_caller(void) +{ + return 0; +} + +/* + * archs can override this function if they must do something + * to disable hook for graph tracer. */ -bool ftrace_graph_is_dead(void) +int __weak ftrace_disable_ftrace_graph_caller(void) { - return kill_ftrace_graph; + return 0; } +#endif /** - * ftrace_graph_stop - set to permanently disable function graph tracincg + * ftrace_graph_stop - set to permanently disable function graph tracing * * In case of an error int function graph tracing, this is called * to try to keep function graph tracing from causing any more harm. @@ -51,7 +60,7 @@ bool ftrace_graph_is_dead(void) */ void ftrace_graph_stop(void) { - kill_ftrace_graph = true; + static_branch_enable(&kill_ftrace_graph); } /* Add a function return address to the trace stack on thread info.*/ @@ -115,15 +124,17 @@ int function_graph_enter(unsigned long ret, unsigned long func, { struct ftrace_graph_ent trace; +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS /* * Skip graph tracing if the return location is served by direct trampoline, - * since call sequence and return addresses is unpredicatable anymore. + * since call sequence and return addresses are unpredictable anyway. * Ex: BPF trampoline may call original function and may skip frame * depending on type of BPF programs attached. */ if (ftrace_direct_func_count && ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE)) return -EBUSY; +#endif trace.func = func; trace.depth = ++current->curr_ret_depth; @@ -333,11 +344,10 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, #endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */ static struct ftrace_ops graph_ops = { - .func = ftrace_stub, - .flags = FTRACE_OPS_FL_RECURSION_SAFE | - FTRACE_OPS_FL_INITIALIZED | + .func = ftrace_graph_func, + .flags = FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID | - FTRACE_OPS_FL_STUB, + FTRACE_OPS_GRAPH_STUB, #ifdef FTRACE_GRAPH_TRAMP_ADDR .trampoline = FTRACE_GRAPH_TRAMP_ADDR, /* trampoline_size is only needed for dynamically allocated tramps */ @@ -387,15 +397,14 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) } } - read_lock(&tasklist_lock); - do_each_thread(g, t) { + rcu_read_lock(); + for_each_process_thread(g, t) { if (start == end) { ret = -EAGAIN; goto unlock; } if (t->ret_stack == NULL) { - atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); t->curr_ret_stack = -1; t->curr_ret_depth = -1; @@ -403,10 +412,10 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) smp_wmb(); t->ret_stack = ret_stack_list[start++]; } - } while_each_thread(g, t); + } unlock: - read_unlock(&tasklist_lock); + rcu_read_unlock(); free: for (i = start; i < end; i++) kfree(ret_stack_list[i]); @@ -415,7 +424,9 @@ free: static void ftrace_graph_probe_sched_switch(void *ignore, bool preempt, - struct task_struct *prev, struct task_struct *next) + struct task_struct *prev, + struct task_struct *next, + unsigned int prev_state) { unsigned long long timestamp; int index; @@ -490,7 +501,6 @@ static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack); static void graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack) { - atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); t->ftrace_timestamp = 0; /* make curr_ret_stack visible before we add the ret_stack */ |