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

[Nick Piggin]

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.

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