linux-kernel - Re: [PATCH] block: do not put mq context in blk_mq_alloc_request

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Date:   Thu, 30 Mar 2017 08:12:28 -0600
From:   Jens Axboe <axboe@...com>
To:     Minchan Kim <minchan@...nel.org>
CC:     <kernel-team@....com>, <linux-block@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, Sagi Grimberg <sagi@...mberg.me>,
        "Omar Sandoval" <osandov@...com>
Subject: Re: [PATCH] block: do not put mq context in blk_mq_alloc_request_hctx

On 03/29/2017 11:20 PM, Minchan Kim wrote:
> In blk_mq_alloc_request_hctx, blk_mq_sched_get_request doesn't
> get sw context so we don't need to put the context with
> blk_mq_put_ctx. Unless, we will see preempt counter underflow.

Good catch, that's definitely a bug. I have applied your patch
for 4.11.

-- 
Jens Axboe