Messages in this thread | | | Date | Thu, 02 Apr 2015 14:01:01 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 1/3] context_tracking: Protect against recursion |
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On 04/02/2015 01:39 PM, Frederic Weisbecker wrote: > Context tracking recursion can happen when an exception triggers in the > middle of a call to a context tracking probe. > > This special case can be caused by vmalloc faults. If an access to a > memory area allocated by vmalloc happens in the middle of > context_tracking_enter(), we may run into an endless fault loop because > the exception in turn calls context_tracking_enter() which faults on > the same vmalloc'ed memory, triggering an exception again, etc... > > Some rare crashes have been reported so lets protect against this with > a recursion counter. > > Reported-by: Dave Jones <davej@redhat.com> > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Rik van Riel <riel@redhat.com> > Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Dave Jones <davej@redhat.com> > Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
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