Re: repeatable slab corruption with LTP msgctl08

From: Andrew Morton
Date: Thu Jun 12 2008 - 05:09:39 EST


On Thu, 12 Jun 2008 10:35:55 +0200 Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:

> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:
> >
> > Doing the same thing on 2.6.26-rc5-mm3, msgctl08 also runs to
> > completion, in 20.9 seconds. So
> >
> > - it got slower
>
> That is because it scales itself to the number of available msg queues.
> So with Nadia's patch there are more and it runs slower.
>
> In fact it seems to start one process per message queue, so perhaps it's
> just running out of processes or something. Ok it should not segfault.
>
> BTW a great way to debug slab corruptions with LTP faster is to run with
> a slab thrasher stress module like http://firstfloor.org/~andi/crasher-26.diff
>

Something like that might be needed. I ran it again and it took 49
minutes to crash.

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