On 21.06.2021 13:58:20, Marc Kleine-Budde wrote:

From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>

commit 8d0caedb759683041d9db82069937525999ada53 upstream

syzbot is reporting hung task at register_netdevice_notifier() [1] and
unregister_netdevice_notifier() [2], for cleanup_net() might perform
time consuming operations while CAN driver's raw/bcm/isotp modules are
calling {register,unregister}_netdevice_notifier() on each socket.

Change raw/bcm/isotp modules to call register_netdevice_notifier() from
module's __init function and call unregister_netdevice_notifier() from
module's __exit function, as with gw/j1939 modules are doing.

Link: https://syzkaller.appspot.com/bug?id=391b9498827788b3cc6830226d4ff5be87107c30 [1]
Link: https://syzkaller.appspot.com/bug?id=1724d278c83ca6e6df100a2e320c10d991cf2bce [2]
Link: https://lore.kernel.org/r/54a5f451-05ed-f977-8534-79e7aa2bcc8f@i-love.sakura.ne.jp (local)
Cc: linux-stable <redacted>
Reported-by: syzbot <redacted>
Reported-by: syzbot <redacted>
Reviewed-by: Kirill Tkhai <redacted>
Tested-by: syzbot <redacted>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[mkl: ported to v4.9.273]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
Hello Greg,

this is a backport of

| 8d0caedb7596 can: bcm/raw/isotp: use per module netdevice notifier

to v4.9.273. Please apply.

This also applies to v4.4.273.

Marc

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