Re: [xen] double fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC

From: Ingo Molnar
Date: Tue Oct 08 2013 - 04:26:35 EST



* Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:

> After enabling CONFIG_DEBUG_OBJECTS_TIMERS=y, it will issue a WARNING followed by a "BUG: ..."

Cool!

> [ 2.802167] parport_pc 00:04: reported by Plug and Play ACPI
> [ 2.803818] parport0: PC-style at 0x378, irq 7 [PCSPP(,...)]
> [ 2.806035] kobject: 'parport_pc.956' (ffff880006dc3820): kobject_release, parent (null) (delayed)
> [ 2.808626] ------------[ cut here ]------------
> [ 2.809776] WARNING: CPU: 1 PID: 1 at /c/wfg/linux/lib/debugobjects.c:260 debug_print_object+0x7c/0x8d()
> [ 2.812433] ODEBUG: init active (active state 0) object type: timer_list hint: (null)
> ......
> [ 3.796079] BUG: unable to handle kernel NULL pointer dereference at (null)

Mind posting the full backtrace? It should show the actual callsite that
zaps the timer. I don't think we got that dump so far, I've only seen
timer list corruption backtraces. (but I haven't read the whole thread.)

Thanks,

Ingo
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