On Wed, Jun 02, 2010 at 02:44:59PM -0400, Don Zickus wrote: > On Tue, Jun 01, 2010 at 04:46:28PM +0200, Jiri Slaby wrote: > > On 06/01/2010 03:50 PM, Don Zickus wrote: > > > On Mon, May 31, 2010 at 04:22:00PM +0200, Jiri Slaby wrote: > > >> Hi, > > >> > > >> with -next I get the following errors while trying to hibernate in > > >> qemu-kvm after the image is stored on disk: > > > > > > Is this the host that is hibernating or the guest? > > > > Guest. > > > > > KVM guests don't emulate the performance counters, so the nmi piece > > > shouldn't be functioning and the soft lockup piece just sits on top of an > > > hrtimer, so off the top of my head it is hard to imagine it intefering > > > with a sata driver. > > > > > > I'll need your whole boot up log to see how the lockup detector > > > initialized itself. > > Ok, so I found out what is causing the problem, not entirely sure why or > what the right fix is, but this patch should do the trick. > > This is probably one of those fixing the symptoms but not the problem patch, > but I don't know enough about suspend/resume to understand what the real > problem is. So the problem is that we stop the cpu hotplug notifying, I guess this prevents some ata callbacks to execute in the cpu hotplug notifier and then provoke this crash. The patch looks ok, but I think you should at least print a message in such case of watchdog failure. Thanks. > > ---->SNIP<--------------------- > [lockup detector] don't return NOTIFY_BAD when cpu goes online for suspend > > KVM guests do not support performance counter emulation, so if the nmi > watchdog piece is compiled in, it will always fail during boot. The > failure returns NOTIFY_BAD when the cpu goes online in the cpu notifier > callback. Returning NOTIFY_BAD causes hibernation to do really bad > things, so avoid doing that. > > The cpu failure shouldn't be a critical failure anyway, so returning > NOTIFY_BAD was probably overstating things. > > Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx> > > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index 6b7fad8..fda9770 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -550,8 +550,7 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) > break; > case CPU_ONLINE: > case CPU_ONLINE_FROZEN: > - if (watchdog_enable(hotcpu)) > - return NOTIFY_BAD; > + watchdog_enable(hotcpu) > break; > #ifdef CONFIG_HOTPLUG_CPU > case CPU_UP_CANCELED: _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
