Re: [Bug #10815] 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0

From: Vegard Nossum
Date: Mon Jun 16 2008 - 09:53:53 EST


On Mon, Jun 16, 2008 at 5:01 AM, Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
> On Sun, Jun 15, 2008 at 04:38:24PM -0700, Linus Torvalds wrote:
>> On Sun, 15 Jun 2008, Paul E. McKenney wrote:
>> >
>> > If that is the right thing to do. I would feel better about it if I
>> > could reproduce the failure.
>>
>> Is there some configuration thing that might make it happen for Alexey but
>> not for you? The only obvious one is the normal PREEMPT thing, but
>> PREEMPT_RCU obviously depends on that, so there must be something else.
>>
>> CONFIG_SMP? CONFIG_NO_HZ? CONFIG_[RT|FAIR]_GROUP_SCHED? There's a number
>> of config options that change scheduling details..
>
> The only way I can "fix" rcutorture here is SMP=n (not maxcpus=1!).
>
> Among things tried and do not matter are NO_HZ, HIGH_RES_TIMERS, turning off
> debugging options (one by one and in bulk), DEBUG_PER_CPU_MAPS, HZ tweaks,
> SCHED_MC.
>
> All of this doesn't help, but SMP=n does.

Maybe this is a stupid suggestion, but SLUB _is_ involved here (in
poisoning the object when it is freed). Do you have SLUB_DEBUG_ON=y or
did you check whether it matters if you have these options on or off?


Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
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