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From:   Jens Axboe <axboe@kernel.dk>
To:     ming.lei@redhat.com, Yu Kuai <yukuai1@huaweicloud.com>,
        john.garry@huawei.com, hare@suse.de
Cc:     linux-block@vger.kernel.org, yukuai3@huawei.com,
        linux-kernel@vger.kernel.org, yi.zhang@huawei.com
In-Reply-To: <20221011142253.4015966-1-yukuai1@huaweicloud.com>
References: <20221011142253.4015966-1-yukuai1@huaweicloud.com>
Subject: Re: [PATCH v2] blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()
Message-Id: <166596258175.7979.3302811091883290568.b4-ty@kernel.dk>
Date:   Sun, 16 Oct 2022 17:23:01 -0600
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
Precedence: bulk

On Tue, 11 Oct 2022 22:22:53 +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> Our syzkaller report a null pointer dereference, root cause is
> following:
> 
> __blk_mq_alloc_map_and_rqs
>  set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs
>   blk_mq_alloc_map_and_rqs
>    blk_mq_alloc_rqs
>     // failed due to oom
>     alloc_pages_node
>     // set->tags[hctx_idx] is still NULL
>     blk_mq_free_rqs
>      drv_tags = set->tags[hctx_idx];
>      // null pointer dereference is triggered
>      blk_mq_clear_rq_mapping(drv_tags, ...)
> 
> [...]

Applied, thanks!

[1/1] blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()
      commit: 76dd298094f484c6250ebd076fa53287477b2328

Best regards,
-- 
Jens Axboe