Pavel Begunkov bd2703b42d io_uring: don't touch sqd->thread off tw add
With IORING_SETUP_SQPOLL all requests are created by the SQPOLL task,
which means that req->task should always match sqd->thread. Since
accesses to sqd->thread should be separately protected, use req->task
in io_req_normal_work_add() instead.

Note, in the eyes of io_req_normal_work_add(), the SQPOLL task struct
is always pinned and alive, and sqd->thread can either be the task or
NULL. It's only problematic if the compiler decides to reload the value
after the null check, which is not so likely.

Cc: stable@vger.kernel.org
Cc: Bui Quang Minh <minhquangbui99@gmail.com>
Reported-by: lizetao <lizetao1@huawei.com>
Fixes: 78f9b61bd8 ("io_uring: wake SQPOLL task when task_work is added to an empty queue")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1cbbe72cf32c45a8fee96026463024cd8564a7d7.1736541357.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10 14:00:25 -07:00
2024-09-01 20:43:24 -07:00
2024-12-01 14:28:56 -08:00

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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