From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, hch@infradead.org
Subject: Re: [PATCH 2/2] block: fix double bio queue when merging in cached request path
Date: Fri, 3 Dec 2021 10:36:02 +0800 [thread overview]
Message-ID: <YamCkkHUDluZLDxE@T590> (raw)
In-Reply-To: <20211202194741.810957-3-axboe@kernel.dk>
On Thu, Dec 02, 2021 at 12:47:41PM -0700, Jens Axboe wrote:
> When we attempt to merge off the cached request path, we return NULL
> if successful. This makes the caller believe that it's should allocate
> a new request, and hence we end up with the bio both merged and associated
> with a new request. This, predictably, leads to all sorts of crashes.
>
> Pass in a pointer to the bio pointer, and clear it for the merge case.
> Then the caller knows that the bio is already queued, and no new requests
> need to get allocated.
>
> Fixes: 5b13bc8a3fd5 ("blk-mq: cleanup request allocation")
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Io hang in io_uring workload can't be triggered any more with this
patch:
Reviewed-by: Ming Lei <ming.lei@redhat.com>
--
Ming
next prev parent reply other threads:[~2021-12-03 2:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 19:47 [PATCH 0/2] Fix bio merge off cached request path Jens Axboe
2021-12-02 19:47 ` [PATCH 1/2] block: get rid of useless goto and label in blk_mq_get_new_requests() Jens Axboe
2021-12-03 6:53 ` Christoph Hellwig
2021-12-02 19:47 ` [PATCH 2/2] block: fix double bio queue when merging in cached request path Jens Axboe
2021-12-03 2:36 ` Ming Lei [this message]
2021-12-03 6:54 ` Christoph Hellwig
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