Messages in this thread | | | Date | Fri, 8 Jun 2012 14:44:47 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2] watchdog: fix for lockup detector breakage on resume |
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On Mon, 07 May 2012 08:54:57 +0530 Anshuman Khandual <khandual@linux.vnet.ibm.com> wrote:
> On Tuesday 01 May 2012 10:52 PM, Sameer Nanda wrote: > > > On the suspend/resume path the boot CPU does not go though an > > offline->online transition. This breaks the NMI detector > > post-resume since it depends on PMU state that is lost when > > the system gets suspended. > > > We should not have allowed the PMU to go with events counting on it across the suspend/resume transition > and find out that the state has been lost. This patch solves the problem of the NMI detector as we restart the > counter again when the boot cpu comes back online during resume. But the original cause (PMU going with > counters into the suspend state) which triggered this problem is still there. May be we should have called > perf_event_exit() on the boot cpu before going into the suspend state. >
That sounds like a nicer solution.
An implementation would be nice ;) I'll keep the original patch on life support until we get all this nailed down.
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