Messages in this thread | | | Subject | Re: [PATCH] tracing: Fix preempt count leak | From | Steven Rostedt <> | Date | Mon, 20 Dec 2010 20:33:59 -0500 |
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On Tue, 2010-12-21 at 08:55 +0800, Li Zefan wrote: > Any comment?
oops, this was buried in my email. I'll look at it tomorrow.
-- Steve
> > 15:47, Li Zefan wrote: > > 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> > > --- > > 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 c380612..5767457 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(); > > }
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