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authorIngo Molnar <mingo@elte.hu>2010-12-08 20:15:26 +0100
committerIngo Molnar <mingo@elte.hu>2010-12-08 20:15:29 +0100
commit8e9255e6a2141e050d51bc4d96dbef494a87d653 (patch)
treef190b142830153eaab05555a93c4f71a144ba3d4 /kernel/trace
parent5091faa449ee0b7d73bc296a93bca9540fc51d0a (diff)
parent6313e3c21743cc88bb5bd8aa72948ee1e83937b6 (diff)
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.c19
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