can: statistics: use atomic access in hot path

In can_send() and can_receive() CAN messages and CAN filter matches are
counted to be visible in the CAN procfs files.

KCSAN detected a data race within can_send() when two CAN frames have
been generated by a timer event writing to the same CAN netdevice at the
same time. Use atomic operations to access the statistics in the hot path
to fix the KCSAN complaint.

Reported-by:  <syzbot+78ce4489b812515d5e4d@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/67cd717d.050a0220.e1a89.0006.GAE@google.com


Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/20250310143353.3242-1-socketcan@hartkopp.net


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>