Re: [PATCH] blk-mq: Fix a recently introduced scsi-mq regression

[Bart Van Assche <bart.vanassche@sandisk.com>]

On 01/29/15 00:52, Ming Lei wrote:
> On Thu, Jan 29, 2015 at 2:28 AM, Bart Van Assche
> <bart.vanassche@sandisk.com> wrote:
>> This patch fixes a use-after-free that was introduced via patch
>> "blk-mq: fix hctx/ctx kobject use-after-free" (commit
>> 76d697d10769; kernel v3.19-rc4) and fixes the following crash:
> 
> Sorry, my fault, I shouldn't have linked mq's release with mq_kobj,
> which may be released before running blk_cleanup_queue().
> 
> Another approach may be to revert the faulty commit and release all
> mq stuff in request queue's release handler(blk_release_queue)
> which should be more safe and simple.

Hello Ming,

How important is the patch with commit ID 76d697d10769 ? Does it have to
be included in kernel v3.19 or can it be postponed until kernel v3.19.1
or kernel v3.19.2 ? If so, how about reverting that patch for kernel
v3.19 and sending a reworked patch to Jens with a "Cc: stable" tag after
the release of kernel v3.19 ? That last patch will then get included in
a stable version of kernel v3.19.

Thanks,

Bart.