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| author | Li Zefan <lizf@cn.fujitsu.com> | 2010-12-09 15:47:56 +0800 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2011-01-07 23:20:02 -0500 |
| commit | 1dbd1951f39e13da579ffe879cce19586d0462de (patch) | |
| tree | faf1ea3208d0e612968a2892917c036a32ff9bda /kernel/trace/trace.c | |
| parent | bd1c8b22b7b81c6f6c4f5c19cb2387da3d02fb0f (diff) | |
| download | lwn-1dbd1951f39e13da579ffe879cce19586d0462de.tar.gz lwn-1dbd1951f39e13da579ffe879cce19586d0462de.zip | |
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/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 6 |
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(); } |