From: Nilay Shroff <nilay@linux.ibm.com>
To: Ming Lei <ming.lei@redhat.com>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org
Cc: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>,
"Christoph Hellwig" <hch@lst.de>,
syzbot+4c7e0f9b94ad65811efb@syzkaller.appspotmail.com
Subject: Re: [PATCH 3/3] block: use blk_mq_no_io() for avoiding lock dependency
Date: Wed, 2 Apr 2025 19:13:56 +0530 [thread overview]
Message-ID: <089a8cf5-bc01-468f-ab96-f04448e034ae@linux.ibm.com> (raw)
In-Reply-To: <20250402043851.946498-4-ming.lei@redhat.com>
On 4/2/25 10:08 AM, Ming Lei wrote:
> Use blk_mq_no_io() to prevent IO from entering queue for avoiding lock
> dependency between freeze lock and elevator lock, and we have got many
> such reports:
>
> Reported-by: syzbot+4c7e0f9b94ad65811efb@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/linux-block/67e6b425.050a0220.2f068f.007b.GAE@google.com/
> Reported-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
> Closes: https://lore.kernel.org/linux-block/7755.1743228130@turing-police/#t
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
I tested this series on my system and this works well as we cut dependency
between ->elevator_lock and ->freeze_lock. However don't we plan to now
model blk_mq_enter_no_io and blk_mq_exit_no_io as lock/unlock for supporting
lockdep? Maybe we don't.
Overall changes looks good to me:
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
next prev parent reply other threads:[~2025-04-02 13:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-02 4:38 [PATCH 0/3] block: fix lock dependency between freeze and elevator lock Ming Lei
2025-04-02 4:38 ` [PATCH 1/3] block: add blk_mq_enter_no_io() and blk_mq_exit_no_io() Ming Lei
2025-04-02 7:55 ` Ming Lei
2025-04-02 13:50 ` Nilay Shroff
2025-04-02 4:38 ` [PATCH 2/3] block: don't call freeze queue in elevator_switch() and elevator_disable() Ming Lei
2025-04-02 13:45 ` Nilay Shroff
2025-04-02 4:38 ` [PATCH 3/3] block: use blk_mq_no_io() for avoiding lock dependency Ming Lei
2025-04-02 13:43 ` Nilay Shroff [this message]
2025-04-03 2:54 ` Ming Lei
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