Re: [PATCH v2 0/2] block,scsi: fixup blk_get_request dead queue scenarios

From: Joe Lawrence
Date: Thu Jun 26 2014 - 23:23:50 EST


On Thu, 26 Jun 2014, Jeff Moyer wrote:

> Jens Axboe <axboe@xxxxxxxxx> writes:
>
> > On 2014-06-26 10:08, Jeff Moyer wrote:
> >> Joe Lawrence <joe.lawrence@xxxxxxxxxxx> writes:
> >>
> >>> v1->v2: incorporate Jeff's feedback in bsg_map_hdr() and Reviewed-by
> >>> tags.
> >>>
> >>> Joe Lawrence (2):
> >>> block,scsi: verify return pointer from blk_get_request
> >>> block,scsi: convert and handle ERR_PTR from blk_get_request
> >>
> >> Jens,
> >>
> >> Can you pick this series up? It actually fixes a NULL pointer
> >> dereference that can happen if (for example) a usb optical drive is
> >> removed while an application is using it.
> >
> > Yeah I'll pick it up, opening up the 3.17 branches soon.
>
> Thanks, Jens. Joe, the patches don't apply anymore... would you mind
> sending an updated set so Jens doesn't have to do the fixups? I think
> you also need to convert blk_mq_alloc_request, I didn't see that in your
> patch.

Hi Jeff,

I have a new set that applies on top of 3.16-rc2... but before posting, I
wasn't sure what needs to be converted w/regard to blk_mq_alloc_request.
As far as I can tell, the new multi-queue block IO queueing implementation
via blk_mq_alloc_request should be safe from this bug as it doesn't
include any dead queue checks that introduce early exits.

Regards,

-- Joe
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