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| author | Ingo Molnar <mingo@elte.hu> | 2010-12-08 20:15:26 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-12-08 20:15:29 +0100 |
| commit | 8e9255e6a2141e050d51bc4d96dbef494a87d653 (patch) | |
| tree | f190b142830153eaab05555a93c4f71a144ba3d4 /kernel/trace | |
| parent | sched: Add 'autogroup' scheduling feature: automated per session task groups (diff) | |
| parent | Merge branches 'x86-fixes-for-linus', 'perf-fixes-for-linus' and 'sched-fixes... (diff) | |
| download | linux-8e9255e6a2141e050d51bc4d96dbef494a87d653.tar.xz linux-8e9255e6a2141e050d51bc4d96dbef494a87d653.zip | |
Merge branch 'linus' into sched/core
Merge reason: we want to queue up dependent cleanup
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 042084157980..c380612273bf 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1283,6 +1283,8 @@ void trace_dump_stack(void) __ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count()); } +static DEFINE_PER_CPU(int, user_stack_count); + void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) { @@ -1301,6 +1303,18 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) if (unlikely(in_nmi())) return; + /* + * prevent recursion, since the user stack tracing may + * trigger other kernel events. + */ + preempt_disable(); + if (__this_cpu_read(user_stack_count)) + goto out; + + __this_cpu_inc(user_stack_count); + + + event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, sizeof(*entry), flags, pc); if (!event) @@ -1318,6 +1332,11 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) save_stack_trace_user(&trace); if (!filter_check_discard(call, entry, buffer, event)) ring_buffer_unlock_commit(buffer, event); + + __this_cpu_dec(user_stack_count); + + out: + preempt_enable(); } #ifdef UNUSED |