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authorLi Zefan <lizf@cn.fujitsu.com>2010-12-09 15:47:56 +0800
committerSteven Rostedt <rostedt@goodmis.org>2011-01-07 23:20:02 -0500
commit1dbd1951f39e13da579ffe879cce19586d0462de (patch)
treefaf1ea3208d0e612968a2892917c036a32ff9bda /kernel/trace
parentbd1c8b22b7b81c6f6c4f5c19cb2387da3d02fb0f (diff)
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tracing: Fix preempt count leak
While running my ftrace stress test, this showed up: BUG: sleeping function called from invalid context at mm/mmap.c:233 ... note: cat[3293] exited with preempt_count 1 The bug was introduced by commit 91e86e560d0b3ce4c5fc64fd2bbb99f856a30a4e ("tracing: Fix recursive user stack trace") Cc: <stable@kernel.org> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4D0089AC.1020802@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f8cf959bad45..dc53ecb80589 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1313,12 +1313,10 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
__this_cpu_inc(user_stack_count);
-
-
event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
- return;
+ goto out_drop_count;
entry = ring_buffer_event_data(event);
entry->tgid = current->tgid;
@@ -1333,8 +1331,8 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
if (!filter_check_discard(call, entry, buffer, event))
ring_buffer_unlock_commit(buffer, event);
+ out_drop_count:
__this_cpu_dec(user_stack_count);
-
out:
preempt_enable();
}