tag 7270975cbf2bcda2769616979d29c19af09b46ea
tagger Marc Kleine-Budde <mkl@pengutronix.de> Wed Apr 05 11:18:15 2023 +0200
object 051737439eaee5bdd03d3c2ef5510d54a478fd05

linux-can-fixes-for-6.3-20230405

commit 051737439eaee5bdd03d3c2ef5510d54a478fd05
author Oliver Hartkopp <socketcan@hartkopp.net> Fri Mar 31 15:19:35 2023 +0200
committer Marc Kleine-Budde <mkl@pengutronix.de> Wed Apr 05 11:16:37 2023 +0200
tree 4b07b9f7b07f389e022c62aeb1b790b16935ea9b
parent 79e19fa79cb5d5f1b3bf3e3ae24989ccb93c7b7b

can: isotp: fix race between isotp_sendsmg() and isotp_release()

As discussed with Dae R. Jeong and Hillf Danton here [1] the sendmsg()
function in isotp.c might get into a race condition when restoring the
former tx.state from the old_state.

Remove the old_state concept and implement proper locking for the
ISOTP_IDLE transitions in isotp_sendmsg(), inspired by a
simplification idea from Hillf Danton.

Introduce a new tx.state ISOTP_SHUTDOWN and use the same locking
mechanism from isotp_release() which resolves a potential race between
isotp_sendsmg() and isotp_release().

[1] https://lore.kernel.org/linux-can/ZB%2F93xJxq%2FBUqAgG@dragonet

v1: https://lore.kernel.org/all/20230331102114.15164-1-socketcan@hartkopp.net
v2: https://lore.kernel.org/all/20230331123600.3550-1-socketcan@hartkopp.net
    take care of signal interrupts for wait_event_interruptible() in
    isotp_release()
v3: https://lore.kernel.org/all/20230331130654.9886-1-socketcan@hartkopp.net
    take care of signal interrupts for wait_event_interruptible() in
    isotp_sendmsg() in the wait_tx_done case
v4: https://lore.kernel.org/all/20230331131935.21465-1-socketcan@hartkopp.net
    take care of signal interrupts for wait_event_interruptible() in
    isotp_sendmsg() in ALL cases

Cc: Dae R. Jeong <threeearcat@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Fixes: 4f027cba8216 ("can: isotp: split tx timer into transmission and timeout")
Link: https://lore.kernel.org/all/20230331131935.21465-1-socketcan@hartkopp.net
Cc: stable@vger.kernel.org
[mkl: rephrase commit message]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>