Re: [patch 1/4] Ignore stolen time in the softlockup watchdog

From: Jeremy Fitzhardinge
Date: Tue Apr 24 2007 - 16:24:28 EST

Jeremy Fitzhardinge wrote:
> Andrew Morton wrote:
>> Well, it _is_ mysterious.
>> Did you try to locate the code which failed? I got lost in macros and
>> include files, and gave up very very easily. Stop hiding, Ingo.
> OK, I've managed to reproduce it. Removing the local_irq_save/restore
> from sched_clock() makes it go away, as I'd expect (otherwise it would
> really be magic). But given that it never seems to touch the softlockup
> during testing, I have no idea what difference it makes...

And sched_clock's use of local_irq_save/restore appears to be absolutely
correct, so I think it must be triggering a bug in either the self-tests
or lockdep itself.

The only way I could actually extract the test code itself was to run
the whole thing through cpp+indent, but it doesn't shed much light.

It's also not clear to me if there are 6 independent failures, or if
they're a cascade.

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