Re: [PATCH, RESEND] locks: fix possible infinite loop in posix deadlock detection

Alan Cox
2007-10-30T15:35:01Z

On Tue, 30 Oct 2007 11:20:02 -0400
"J. Bruce Fields" <bfields@fieldses.org> wrote:

> From: J. Bruce Fields <bfields@citi.umich.edu>
>
> It's currently possible to send posix_locks_deadlock() into an infinite
> loop (under the BKL).
>
> For now, fix this just by bailing out after a few iterations. We may
> want to fix this in a way that better clarifies the semantics of
> deadlock detection. But that will take more time, and this minimal fix
> is probably adequate for any realistic scenario, and is simple enough to
> be appropriate for applying to stable kernels now.
>
> Thanks to George Davis for reporting the problem.
>
> Cc: "George G. Davis" <gdavis@mvista.com>
> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Acked-by: Alan Cox <alan@redhat.com>

Its a good fix for now and I doubt any real world user has that complex a
locking pattern to break.