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: 4f027cba ("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>
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