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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-27 07:28:17 +0900 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-27 07:28:17 +0900 |
| commit | d2f30c73aba19be828c759edcd21140390cd06e4 (patch) | |
| tree | b9bad75b11e21680f8f9443f0143d62be23cae78 /kernel/trace/trace.c | |
| parent | 1b065fdff1c950d96e4c571abe873a9a8aaa6d51 (diff) | |
| parent | 02a9d03772aa1ff33a26180a2da0bfb191240eda (diff) | |
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf symbols: Remove incorrect open-coded container_of()
perf record: Handle restrictive permissions in /proc/{kallsyms,modules}
x86/kprobes: Prevent kprobes to probe on save_args()
irq_work: Drop cmpxchg() result
perf: Fix owner-list vs exit
x86, hw_nmi: Move backtrace_mask declaration under ARCH_HAS_NMI_WATCHDOG
tracing: Fix recursive user stack trace
perf,hw_breakpoint: Initialize hardware api earlier
x86: Ignore trap bits on single step exceptions
tracing: Force arch_local_irq_* notrace for paravirt
tracing: Fix module use of trace_bprintk()
Diffstat (limited to 'kernel/trace/trace.c')
| -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 |