can: j1939: change j1939_netdev_lock type to mutex

It turns out access to j1939_can_rx_register() needs to be serialized,
otherwise j1939_priv can be corrupted when parallel threads call
j1939_netdev_start() and j1939_can_rx_register() fails. This issue is
thoroughly covered in other commit which serializes access to
j1939_can_rx_register().

Change j1939_netdev_lock type to mutex so that we do not need to remove
GFP_KERNEL from can_rx_register().

j1939_netdev_lock seems to be used in normal contexts where mutex usage
is not prohibited.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Suggested-by: Alexey Khoroshilov <[email protected]>
Signed-off-by: Fedor Pchelkin <[email protected]>
Tested-by: Oleksij Rempel <[email protected]>
Acked-by: Oleksij Rempel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: [email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>

0 files changed, 0 insertions, 0 deletions