Messages in this thread | | | Date | Mon, 12 Oct 2009 23:28:11 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/2] oprofile: fix race condition in event_buffer free |
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* Robert Richter <robert.richter@amd.com> wrote:
> On 09.10.09 21:33:29, Robert Richter wrote: > > From: David Rientjes <rientjes@google.com> > > > > Looking at the 2.6.31-rc9 code, it appears there is a race condition > > in the event_buffer cleanup code path (shutdown). This could lead to > > kernel panic as some CPUs may be operating on the event buffer AFTER > > it has been freed. The attached patch solves the problem and makes > > sure CPUs check if the buffer is not NULL before they access it as > > some may have been spinning on the mutex while the buffer was being > > freed. > > > > The race may happen if the buffer is freed during pending reads. But > > it is not clear why there are races in add_event_entry() since all > > workqueues or handlers are canceled or flushed before the event buffer > > is freed. > > > > Signed-off-by: David Rientjes <rientjes@google.com> > > Signed-off-by: Stephane Eranian <eranian@google.com> > > Signed-off-by: Robert Richter <robert.richter@amd.com> > > Ingo, > > you can also pull the patches from here: > > git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile.git urgent > > Thanks.
Pulled, thanks Robert!
Ingo
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