Re: kernel panic after suspend/resume (was: Linux 3.4-rc3)

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday, April 17, 2012, Linus Torvalds wrote:
> On Tue, Apr 17, 2012 at 8:24 AM, Sven Joachim <svenjoac@gmx.de> wrote:
> >
> > With Linux 3.4-rc3, I'm experiencing crashes after resuming from
> > suspend, not immediately but after a few minutes.  This has happened
> > three times so far, note that 3.4-rc2 worked fine.
> 
> Hmm. Looks like "global_clock_event->event_handler" is NULL. Which
> doesn't make any sense what-so-ever, but clearly it is.
> 
>  Added Ingo and Thomas to the cc, since that's a very x86
> timer-looking thing. And Rafael since it's about suspend/resume. I do
> wonder if it's some odd memory corruption due to a wild pointer. Of
> course, if it's somewhat repeatable, that's some *seriously* odd
> corruption, though. So that sounds unlikely too - but that
> global_clock_event thing looks odd.
> 
> Oh: guys, one thing to look at is that "lapic_cal_handler" thing.
> Weren't there some changes to timer calibration wrt SMP lately? Not in
> -rc3, but we had some calibrate_delay() changes - skipping them on
> other CPU's when the TSC was reliable, and irq disable things.
> 
> Maybe the calibration at resume now does something different?
> 
> Two questions:
> 
>  - if it is reasonably repeatable, can you try to bisect it? There's
> just under 400 commits in between rc2 and rc3, and you don't really
> need to do a full bisect, but if you do just four bisections, it
> should narrow it down to just 25 commits or so.
> 
>  - how sure are you that rc2 is fine? I don't see anything suspicious
> in this area since rc2, so I would ask you to really test it very well
> to make sure it really was introduced after rc2.
> 
> Thomas, Ingo, Rafael - any ideas?

Well, commit fa4da365bc7772c kind of looks like it might be the source of
this trouble.  Sven, can you try to revert it, please?

Rafael