Messages in this thread | | | Subject | Re: [PATCH 2/2 v2] watchdog: Always return NOTIFY_OK during cpu up/down events | From | Peter Zijlstra <> | Date | Thu, 17 Mar 2011 10:12:49 +0100 |
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On Mon, 2011-03-07 at 16:37 -0500, Don Zickus wrote: > > This patch addresses a couple of problems. One was the case when the > hardlockup failed to start, it also failed to start the softlockup. > There were valid cases when the hardlockup shouldn't start and that > shouldn't block the softlockup (no lapic, bios controls perf > counters). > > The second problem was when the hardlockup failed to start on boxes > (from a no lapic or bios controlled perf counter case), it reported > failure to the cpu notifier chain. This blocked the notifier from > continuing to start other more critical pieces of cpu bring-up (in > our case based on a 2.6.32 fork, it was the mce). As a result, > during soft cpu online/offline testing, the system would panic > when a cpu was offlined because the cpu notifier would succeed in > processing a watchdog disable cpu event and would panic in the mce > case as a result of un-initialized variables from a never executed > cpu up event. > > I realized the hardlockup/softlockup cases are really just debugging > aids and should never impede the progress of a cpu up/down event. > Therefore I modified the code to always return NOTIFY_OK and instead > rely on printks to inform the user of problems. > > Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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