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

[Davidlohr Bueso]

Adding Oleg.

On Mon, 2014-04-28 at 14:55 -0700, Linus Torvalds wrote:
> On Mon, Apr 28, 2014 at 2:20 PM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > That said, the bug does seem to be that some path doesn't invalidate
> > the vmacache sufficiently, or something inserts a vmacache entry into
> > the current process when looking up a remote process or whatever.
> > Davidlohr, ideas?
> 
> Maybe we missed some use_mm() call. That will change the current mm
> without flushing the vma cache. The code considers kernel threads to
> be bad targets for vma caching for this reason (and perhaps others),
> but maybe we missed something.
> 
> I wonder if we should just invalidate the vma cache in use_mm(), and
> remote the "kernel tasks are special" check.
> 
> Srivatsa, are you doing something peculiar on that system that would
> trigger this? I see some kdump failures in the log, anything else?

Is this perhaps a KVM guest? fwiw I see CONFIG_KVM_ASYNC_PF=y which is a
user of use_mm().

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/