Re: dcache shrink list corruption?

[Al Viro <viro@ZenIV.linux.org.uk>]

On Wed, Apr 30, 2014 at 11:15:15AM +0200, Miklos Szeredi wrote:
> On Tue, Apr 29, 2014 at 07:56:13PM -0700, Linus Torvalds wrote:
> > On Tue, Apr 29, 2014 at 7:31 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > >
> > > OK, aggregate diff follows, more readable splitup (3 commits) attached.
> > > It seems to survive beating here; testing, review and comments are
> > > welcome.
> > 
> > Miklos, did you have some particular load that triggered this, or was
> > it just some reports? It would be really good to get this patch some
> > stress-testing.
> > 
> > I like how the patch removes more lines than it adds, but apart from
> > that it's hard to read the patch (even the split-out ones) and say
> > anything more about it. I think this needs a *lot* of testing.
> 
> IBM is triggering this with the host01 test from the LTP suite.  I haven't yet
> tried to reproduce it.

Could you repost their report?  So far I hadn't managed to get actual list
corruption on mainline kernel - it definitely is possible, but on all
testcases so far the race window is too narrow.  So if they have a reproducer
that doesn't take an insane amount of time, I'd really like to see it...