Re: mm: BUG: Bad rss-counter state
From: Dave Jones
Date: Wed Jan 22 2014 - 20:53:08 EST
On Wed, Jan 22, 2014 at 05:39:25PM -0800, David Rientjes wrote:
> > While fuzzing with trinity running inside a KVM tools guest using latest -next
> > kernel,
> > I've stumbled on a "mm: BUG: Bad rss-counter state" error which was pretty
> > non-obvious
> > in the mix of the kernel spew (why?).
> It's not a fatal condition and there's only a few possible stack traces
> that could be emitted during the exit() path. I don't see how we could
> make it more visible other than its log-level which is already KERN_ALERT.
> > I've added a small BUG() after the printk() in check_mm(), and here's the full
> > output:
> Worst place to add it :) At line 562 of kernel/fork.c in linux-next
> you're going to hit BUG() when there may be other counters that are also
> bad and they don't get printed.
> > [ 318.334905] BUG: Bad rss-counter state mm:ffff8801e6dec000 idx:0 val:1
> So our mm has a non-zero MM_FILEPAGES count, but there's nothing that was
> cited that would tell us what that is so there's not much to go on, unless
> someone already recognizes this as another issue. Is this reproducible on
> 3.13 or only on linux-next?
Sasha, is this the current git tree version of Trinity ?
(I'm wondering if yesterdays munmap changes might be tickling this bug).
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