Re: BUG: Bad page map in process udevd (anon_vma: (null)) in2.6.38-rc4

From: Ingo Molnar
Date: Thu Feb 17 2011 - 11:35:54 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> And in addition, I don't see why others wouldn't see it (I've got
> DEBUG_PAGEALLOC and SLUB_DEBUG_ON turned on myself, and I know others
> do too).

I've done extensive randconfig testing and no crash triggers for typical workloads
on a typical dual-core PC. If there's a generic crashes in there my tests tend to
trigger them at least 10x as often as regular testers ;-) But the tests are still
only statistical so the race could simply be special and missed by the tests.

> So I'm wondering what triggers it. Must be something subtle.

I think what Michal did before he got the corruption seemed somewhat atypical:
suspend/resume and udevd wifi twiddling, right?

Now, Eric's crashes look similar - and he does not seem to have done anything
special to trigger the crashes.

Eric, could you possibly describe your system in a bit more detail, does it do
suspend and does the box use wifi actively? Anything atypical in your setup or usage
that doesnt match a bog-standard whitebox PC with LAN? Swap to file? NFS? FUSE?
Anything that is even just borderline atypical.

Thanks,

Ingo
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