Re: [BUG] kernel BUG at mm/vmacache.c:85!

From: Srivatsa S. Bhat
Date: Tue Apr 29 2014 - 06:00:33 EST


On 04/29/2014 03:55 AM, Linus Torvalds wrote:
> On Mon, Apr 28, 2014 at 3:14 PM, Davidlohr Bueso <davidlohr@xxxxxx> wrote:
>>
>> I think that returning some stale/bogus vma is causing those segfaults
>> in udev. It shouldn't occur in a normal scenario. What puzzles me is
>> that it's not always reproducible. This makes me wonder what else is
>> going on...
>
> I've replaced the BUG_ON() with a WARN_ON_ONCE(), and made it be
> unconditional (so you don't have to trigger the range check).
>
> That might make it show up earlier and easier (and hopefully closer to
> the place that causes it). Maybe that makes it easier for Srivatsa to
> reproduce this. It doesn't make *my* machine do anything different,
> though.
>
> Srivatsa? It's in current -git.
>

I tried this, but still nothing so far. I rebooted 10-20 times, and also
tried multiple runs of multi-threaded ebizzy and kernel compilations,
but none of this hit the warning.

Is there anything more specific I can run to increase the chances of
hitting this? I guess a test-case might be too much to ask since I'm
the first one hitting this, but if anybody has suggestions of scenarios
which have a higher likelihood of hitting this (like running multi-
threaded workloads or whatever), I could probably give it a try as well.

Thank you!

Regards,
Srivatsa S. Bhat

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