Re: BUG: Bad page map in process udevd (anon_vma: (null)) in 2.6.38-rc4

From: Linus Torvalds
Date: Wed Feb 16 2011 - 15:52:18 EST


On Wed, Feb 16, 2011 at 12:09 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> That said, neither 0x1e68 nor 0xe68 seems to be in the main vmlinux
> file. But I haven't checked modules yet.

There's no obvious clues in modules either. Sad. I was really hoping
for some "oh, there's a list_head at offset 0x1e68 of structure 'xyz',
that's obviously it".

So maybe it really is something like a pointer to some on-stack data,
and the 0x1e68 offset is just a random offset off the beginning of the
stack (it's in the right range). The stack is still one of the few
obvious 8kB allocations we have...

CONFIG_DEBUG_PAGEALLOC really should catch it in that case, though.

Linus
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