From: Jens Axboe <axboe@kernel.dk>
To: Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
Josef Bacik <josef@toxicpanda.com>
Cc: kernel-team@fb.com, linux-block@vger.kernel.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
Ming Lei <ming.lei@redhat.com>
Subject: Re: [PATCH] blkcg: handle dying request_queue when associating a blkg
Date: Wed, 12 Dec 2018 17:43:58 -0700 [thread overview]
Message-ID: <217c7b15-d54a-b51d-8b1a-c2ad0d404721@kernel.dk> (raw)
In-Reply-To: <20181211230308.66276-1-dennis@kernel.org>
On 12/11/18 4:03 PM, Dennis Zhou wrote:
> Between v3 [1] and v4 [2] of the blkg association series, the
> association point moved from generic_make_request_checks(), which is
> called after the request enters the queue, to bio_set_dev(), which is when
> the bio is formed before submit_bio(). When the request_queue goes away,
> the blkgs supporting the request_queue are destroyed and then the
> q->root_blkg is set to %NULL.
>
> This patch adds a %NULL check to blkg_tryget_closest() to prevent the
> NPE caused by the above. It also adds a guard to see if the
> request_queue is dying when creating a blkg to prevent creating a blkg
> for a dead request_queue.
Applied, thanks Dennis.
--
Jens Axboe
prev parent reply other threads:[~2018-12-13 0:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 23:03 Dennis Zhou
2018-12-11 23:16 ` Bart Van Assche
2018-12-12 4:06 ` Dennis Zhou
2018-12-12 23:54 ` Bart Van Assche
2018-12-13 15:47 ` Dennis Zhou
2018-12-13 0:43 ` Jens Axboe [this message]
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