Re: xfs deadlock in stable kernel 3.0.4

Christoph Hellwig
2011-09-20T16:02:33Z

On Tue, Sep 20, 2011 at 12:09:34PM +0200, Stefan Priebe - Profihost AG wrote:
> Hi,
>
> any idea how to get deeper into this? I've tried using kgdb but
> strangely the error does not occur when kgdb is remote attached.
> When i unattach kgdb and restart bonnie the error happens again.
>
> So it seems to me a little bit like a timing issue?

Sounds like it.

Can you summarize all the data that we gather over this thread into one
summary, e.g.

- what kernel does it happens? Seems like 3.0 and 3.1 hit it easily,
2.6.38 some times, 2.6.32 is fine. Did you test anything between
2.6.32 and 2.6.38?
- what hardware hits it often/sometimes/never?
- what is the fs geometry?
- what is the hardware?
- is this a 32 or 64-bit kernel, or do you run both?

I'm pretty sure most got posted somewhere, but let's get a summary
as things was a bit confusing sometimes.

Note that 2.6.38 moved the whole log grant code to a lockless algorithm,
so this might be a likely culprit if you're managing to hit race windows
no one else does, i.e. this really is a timing issue.