Re: 2.6.0-test8, DEBUG_SLAB, oops in as_latter_request()

[Nick Piggin]

Jens Axboe wrote:

> On Mon, Oct 20 2003, Nick Piggin wrote:
>
> > Andrew Morton wrote:
> >
> >
> > > Peter Osterlund <petero2@xxxxxxxxx> wrote:
> > >
> > >
> > > > I was running 2.6.0-test8 compiled with CONFIG_DEBUG_SLAB=y. When
> > > > testing the CDRW packet writing driver, I got an oops in
> > > > as_latter_request. (Full oops at the end of this message.) It is
> > > > repeatable and happens because arq->rb_node.rb_right is uninitialized.
> > > deadline seems to have the same problem.
> > >
> > > We may as well squish this with the big hammer?
> > Thanks for the report, Peter.
> >
> > The request is a special request, so either blk_attempt_remerge should
> > never be called on it, or blk_attempt_remerge (or as_latter_request) should
> > check for this. Its up to Jens.
> >
> > I would say to stick something like
> > if (!rq_mergeable(rq))
> >   return;
> >
> > into blk_attempt_remerge.
> >
> > I'd say we shouldn't expect drivers to try to get this right.
>
> attempt_merge() already includes such a check. To me it looks really
> buggy that elv_latter_request() cannot be called on non-fs requests, I'd
> rather get that fixed like Peter suggests. elv_latter_request() should
> work on all requests in the io sched queue, period.

I don't have a problem with that. Peter's patch it is.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/