Ming Lei dd24f87f65 ublk: fix dead loop when canceling io command
Commit:

f40139fde5 ("ublk: fix race between io_uring_cmd_complete_in_task and
		ublk_cancel_cmd")

adds a request state check in ublk_cancel_cmd(), and if the request is
started, skips canceling this uring_cmd.

However, the current uring_cmd may be in ACTIVE state, without block
request coming to the uring command. Meantime, if the cached request in
tag_set.tags[tag] has been delivered to ublk server and reycycled, then
this uring_cmd can't be canceled.

ublk requests are aborted in ublk char device release handler, which
depends on canceling all ACTIVE uring_cmd. So it causes a dead loop.

Fix this issue by not taking a stale request into account when canceling
uring_cmd in ublk_cancel_cmd().

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Closes: https://lore.kernel.org/linux-block/mruqwpf4tqenkbtgezv5oxwq7ngyq24jzeyqy4ixzvivatbbxv@4oh2wzz4e6qn/
Fixes: f40139fde5 ("ublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250515162601.77346-1-ming.lei@redhat.com
[axboe: rewording of commit message]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-15 10:53:41 -06:00
2024-09-01 20:43:24 -07:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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