| Date | Tue, 15 Feb 2011 16:12:38 -0800 | From | Greg KH <> | Subject | [101/272] tracing: Fix preempt count leak |
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2.6.37-stable review patch. If anyone has any objections, please let us know.
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From: Li Zefan <lizf@cn.fujitsu.com>
commit 1dbd1951f39e13da579ffe879cce19586d0462de upstream.
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")
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4D0089AC.1020802@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/trace/trace.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1313,12 +1313,10 @@ ftrace_trace_userstack(struct ring_buffe __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_buffe 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(); }
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