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From:   Jens Axboe <axboe@kernel.dk>
To:     Tejun Heo <tj@kernel.org>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        darklight2357@icloud.com, Josef Bacik <josef@toxicpanda.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        cgroups@vger.kernel.org
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References: <Y5TQ5gm3O4HXrXR3@slm.duckdns.org>
Subject: Re: (subset) [PATCH 1/2 block/for-6.2] blk-iolatency: Fix memory leak
 on add_disk() failures
Message-Id: <167104700802.18171.11122547200509229739.b4-ty@kernel.dk>
Date:   Wed, 14 Dec 2022 12:43:28 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Precedence: bulk


On Sat, 10 Dec 2022 08:33:10 -1000, Tejun Heo wrote:
> When a gendisk is successfully initialized but add_disk() fails such as when
> a loop device has invalid number of minor device numbers specified,
> blkcg_init_disk() is called during init and then blkcg_exit_disk() during
> error handling. Unfortunately, iolatency gets initialized in the former but
> doesn't get cleaned up in the latter.
> 
> This is because, in non-error cases, the cleanup is performed by
> del_gendisk() calling rq_qos_exit(), the assumption being that rq_qos
> policies, iolatency being one of them, can only be activated once the disk
> is fully registered and visible. That assumption is true for wbt and iocost,
> but not so for iolatency as it gets initialized before add_disk() is called.
> 
> [...]

Applied, thanks!

[1/2] blk-iolatency: Fix memory leak on add_disk() failures
      commit: 813e693023ba10da9e75067780f8378465bf27cc

Best regards,
-- 
Jens Axboe