On 10.03.25 16:04, Vincent Mailhol wrote:
On Mon. 10 Mar 2025 à 23:34, Oliver Hartkopp <socketcan@xxxxxxxxxxxx> wrote:
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Maybe add a Fixes: tag?
I'm not sure about if we should provide a Fixes tag here.
The code is from the initial commit in 2008:
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/can/af_can.c?id=0d66548a10cbbe0ef256852d63d30603f0f73f9b
But it never created any problems and it is also not that relevant if we
have a packet counter which is +/- 1 correct just to be displayed in the
procfs for users that accidentally know about this feature.
If we add a Fixes tag the patch is backported to many stable kernels.
Not sure if it's worth it.
For future KCSAN tests we are safe then.
Best regards,
Oliver
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Notwithstanding of above remark:
Reviewed-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
Yours sincerely,
Vincent Mailhol
