From: Jens Axboe <axboe@kernel.dk>
To: Ming Lei <tom.leiming@gmail.com>, linux-block@vger.kernel.org
Cc: Caleb Sander Mateos <csander@purestorage.com>,
Uday Shankar <ushankar@purestorage.com>
Subject: Re: [PATCH] ublk: reject FETCH from non-userspace context
Date: Fri, 1 May 2026 04:34:11 -0600 [thread overview]
Message-ID: <9efbd035-b40e-4155-8382-b42acff75a9e@kernel.dk> (raw)
In-Reply-To: <20260501085216.905401-1-tom.leiming@gmail.com>
On 5/1/26 2:52 AM, Ming Lei wrote:
> __ublk_fetch() sets io->task to current, which is later checked
> against io_uring_cmd_get_task() in ublk_uring_cmd_cancel_fn().
> With REQ_F_FORCE_ASYNC, the FETCH uring_cmd can be issued from
> task work, which can be run from io_uring's fallback workqueue,
> causing a task mismatch and triggering the WARN in cancel_fn.
>
> Reject FETCH if current is not a real userspace task, and it is
> reasonable for failing it in case of io_uring fallback.
I think this should be caught in ublk_ch_uring_cmd_cb(), which
should not hit ublk_ch_uring_cmd_local() if tw.cancel is true.
fallback work should just be terminated, not be issued.
--
Jens Axboe
next prev parent reply other threads:[~2026-05-01 10:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-01 8:52 [PATCH] ublk: reject FETCH from non-userspace context Ming Lei
2026-05-01 10:34 ` Jens Axboe [this message]
2026-05-01 10:36 ` Ming Lei
2026-05-01 10:38 ` Jens Axboe
2026-05-01 10:54 ` Ming Lei
2026-05-01 11:05 ` Jens Axboe
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