Messages in this thread | | | Date | Fri, 18 Mar 2011 11:23:53 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/2 v2] watchdog, nmi: Allow hardlockup to panic by default |
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On Fri, 18 Mar 2011 13:19:32 -0400 Don Zickus <dzickus@redhat.com> wrote:
> On Thu, Mar 17, 2011 at 06:50:13PM -0700, Andrew Morton wrote: > > On Mon, 7 Mar 2011 16:37:39 -0500 Don Zickus <dzickus@redhat.com> wrote: > > > > > Add a Kconfig option to allow users to set the hardlockup to panic > > > by default. Also add in a 'nmi_watchdog=nopanic' to override this. > > > > > > > Changelog forgot to tell us "why". > > Yeah, sorry about that. > > When a cpu is considered stuck, instead of limping along and just printing > a warning, it is sometimes preferred to just panic, let kdump capture the > vmcore and reboot. This gets the machine back into a stable state quickly > while saving the info that got it into a stuck state to begin with.
Ah, makes sense, thanks. I updated the changelog.
> > > > > > Format: [state][,regs][,debounce][,die] > > > > > > nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels > > > - Format: [panic,][num] > > > + Format: [panic,][nopanic,][num] > > > > It would be better to support panic=[0|1], if that can be simply done > > in a back-compatible fashion. > > I am open to the idea, just can't figure the best way to implement that in > a backwards compatible way.
It's not worth busting a gut over ;)
> Personally I was wondering if there were situations where you would _not_ > want it to panic. If the cpu is stuck spinning after 60 seconds, the odds > of it freeing itself is low and you are probably stuck rebooting anyway. > > > > > > > static int __init hardlockup_panic_setup(char *str) > > > { > > > if (!strncmp(str, "panic", 5)) > > > hardlockup_panic = 1; > > > + else if (!strncmp(str, "nopanic", 5)) > > > > s/5/7/ > > doh. > > I can send a refreshed patch with the above changes.
I fixed that up.
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