d9c2ba65e6
With patch [1], isotp_poll was updated to also queue the poller in the so->wait queue, which is used for send state changes. Since the queue now also contains polling tasks that are not interested in sending, the queue fill state can no longer be used as an indication of send readiness. As a consequence, nonblocking writes can lead to a race and lock-up of the socket if there is a second task polling the socket in parallel. With this patch, isotp_sendmsg does not consult wq_has_sleepers but instead tries to atomically set so->tx.state and waits on so->wait if it is unable to do so. This behavior is in alignment with isotp_poll, which also checks so->tx.state to determine send readiness. V2: - Revert direct exit to goto err_event_drop [1] https://lore.kernel.org/all/20230331125511.372783-1-michal.sojka@cvut.cz Reported-by: Maxime Jayat <maxime.jayat@mobile-devices.fr> Closes: https://lore.kernel.org/linux-can/11328958-453f-447f-9af8-3b5824dfb041@munic.io/ Signed-off-by: Lukas Magel <lukas.magel@posteo.net> Reviewed-by: Oliver Hartkopp <socketcan@hartkopp.net> Fixes: 79e19fa79cb5 ("can: isotp: isotp_ops: fix poll() to not report false EPOLLOUT events") Link: https://github.com/pylessard/python-udsoncan/issues/178#issuecomment-1743786590 Link: https://lore.kernel.org/all/20230827092205.7908-1-lukas.magel@posteo.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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 Restructured Text 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.