Re: block, bfq: NULL pointer dereference in bfq_rq_pos_tree_lookup()

[Mike Galbraith]

On Mon, 2021-05-03 at 14:41 +0200, Mike Galbraith wrote:
> On Mon, 2021-05-03 at 11:52 +0200, Paolo Valente wrote:
> > Hi Mike,
> > I've waited a little bit before replying, because I've worked on a dev
> > patch series, for debugging another crash. I'd like to use
> > this series for your failure too, as the OOPS you report
> > unfortunately does not ring any bell :(
> >
> > So, could you please try to apply this patch series?  If it doesn't
> > apply, I'll rebase it.
>
> This bug isn't deterministic, but I can wedge your set into my devel
> trees, and see if anything falls out.

What fell out was not the least bit useful.  After days of box working
just fine despite bug being given ample enticement, it didn't take the
bait.  I then build master sans patch set, which exploded on its very
first distro build, after which bug (snickered mightily and) went back
to into hiding.

	-Mike