Re: [patch 02/52] fs: fix superblock iteration race

Chris Clayton
2010-06-29T20:38:51Z

On Tuesday 29 June 2010, Nick Piggin wrote:
> On Tue, Jun 29, 2010 at 09:04:33PM +0100, Chris Clayton wrote:
> > On Tuesday 29 June 2010, Linus Torvalds wrote:
> > > On Tue, Jun 29, 2010 at 10:52 AM, Linus Torvalds
> > >
> > > <torvalds@linux-foundation.org> wrote:
> > > > Look for "2.6.35-rc3 oops trying to suspend" on lkml, for example. No
> > > > guarantee that it's the same thing, but it's "iterate_supers()"
> > > > getting an oops [..]
> > >
> > > Also, "Oops during closedown with 2.6.35-rc3-git3" is an
> > > iterate_supers oops (in the jpg) and Chris says it's repeatable for
> > > him.
> > >
> > > Chris - you could try testing current -git now that I've merged Nick's
> > > patch. It's commit 57439f878af ("fs: fix superblock iteration race"),
> > > and I just pushed it out (so it might take a few minutes to mirror out
> > > to the public git trees, but it should be there shortly).
> >
> > Well, it was repeatable this morning, but despite 30+ shutdowns this
> > evening, I haven't had a single oops. Perhaps I'm just not doing enough
> > computing stuff between startup and shutdown to create the conditions
> > under which I got the oopses this morning. Moreover, I've been using this
> > kernel every day with, maybe two or three shutdowns a day, for two weeks
> > or so now (since just after Linus went on vacation) with no oopses. (The
> > kernel is -rc3 + John Fastabend's "net: fix deliver_no_wcard regression
> > on loopback device" patch).
> >
> > I'll spend a couple of hours doing stuff and see if I can generate an
> > oops. Trouble is, of course, that when I pull and build the latest and
> > greatest, I won't know why I'm not getting oopses, assuming I don't.
>
> Don't worry too much if you can't reproduce. I'd say it is likely to be
> this bug, and if so, it is going to depend significantly on timing and
> ordering of mounts/umounts.

Yes, that makes sense. I did quite a bit of copying files to and from USB
storage devices this morning. I've got some more to do, so I'll see what that
produces.

--
The more I see, the more I know. The more I know, the less I understand.
Changing Man - Paul Weller