linux crash behavior

linux crash behavior

[George Shuklin]

Good day.

I found that xen_panic_event (in arch/x86/xen/enlighten.c) ignore sysctl
settings for kernel.panic, which declare delay between crash and crash
consequences. 

F.e. if we do this in:

sysctl kernel.panic=30
echo c >/proc/sysrq-trigger

I expect at least 30s of crashdump on screen, not instant domain
disappearance.

Is this feature or bug?

Thanks.

Re: linux crash behavior

[Andrew Cooper]

On 17/08/11 12:14, George Shuklin wrote:
> Good day.
>
> I found that xen_panic_event (in arch/x86/xen/enlighten.c) ignore sysctl
> settings for kernel.panic, which declare delay between crash and crash
> consequences. 

Is this dom0 or domU, and which Xen and Linux version?

~Andrew

> F.e. if we do this in:
>
> sysctl kernel.panic=30
> echo c >/proc/sysrq-trigger
>
> I expect at least 30s of crashdump on screen, not instant domain
> disappearance.
>
> Is this feature or bug?
>
> Thanks.
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com

Re: linux crash behavior

[George Shuklin]

В Срд, 17/08/2011 в 12:21 +0100, Andrew Cooper пишет:
> On 17/08/11 12:14, George Shuklin wrote:
> > Good day.
> >
> > I found that xen_panic_event (in arch/x86/xen/enlighten.c) ignore sysctl
> > settings for kernel.panic, which declare delay between crash and crash
> > consequences. 
> 
> Is this dom0 or domU, and which Xen and Linux version?


I think this apply to domU and dom0. 

I saw this  in source of vanilla  3.0/3.1rc2, and I saw this behaivor
in 2.6.34-xen (suse kernel), and even it 2.6.18-xen (rhel5.5 kernel).

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob_plain;f=arch/x86/xen/enlighten.c;hb=HEAD


static void xen_crash_shutdown(struct pt_regs *regs)
{
	xen_reboot(SHUTDOWN_crash);
}

static int
xen_panic_event(struct notifier_block *this, unsigned long event, void
*ptr)
{
	xen_reboot(SHUTDOWN_crash);
	return NOTIFY_DONE;
}

Re: linux crash behavior

[Ian Campbell]

On Wed, 2011-08-17 at 12:14 +0100, George Shuklin wrote:
> Good day.
> 
> I found that xen_panic_event (in arch/x86/xen/enlighten.c) ignore sysctl
> settings for kernel.panic, which declare delay between crash and crash
> consequences. 
> 
> F.e. if we do this in:
> 
> sysctl kernel.panic=30
> echo c >/proc/sysrq-trigger
> 
> I expect at least 30s of crashdump on screen, not instant domain
> disappearance.
> 
> Is this feature or bug?

A bug IMHO.

Ian.