Re: [PATCH] can: canxl: Fix unremoved canxl_packet in can_exit()

Oliver Hartkopp <socketcan@xxxxxxxxxxxx> · Mon, 31 Oct 2022 10:51:26 +0100

On 31.10.22 04:30, Chen Zhongjin wrote:
In can_init(), dev_add_pack(&canxl_packet) is added but not removed in
can_exit(). It break the packet handler list and can make kernel panic
when can_init() for the second time.

modprobe can && rmmod can
rmmod xxx && modprobe can

BUG: unable to handle page fault for address: fffffbfff807d7f4
RIP: 0010:dev_add_pack+0x133/0x1f0
Call Trace:
  <TASK>
  can_init+0xaa/0x1000 [can]
  do_one_initcall+0xd3/0x4e0
  ...

Fixes: fb08cba12b52 ("can: canxl: update CAN infrastructure for CAN XL frames")
Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>

Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>

Thanks for the finding!

Best regards,
Oliver

---
  net/can/af_can.c | 1 +
  1 file changed, 1 insertion(+)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 9503ab10f9b8..5e9e3e1e9825 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -902,6 +902,7 @@ static __init int can_init(void)
  static __exit void can_exit(void)
  {
  	/* protocol unregister */
+	dev_remove_pack(&canxl_packet);
  	dev_remove_pack(&canfd_packet);
  	dev_remove_pack(&can_packet);
  	sock_unregister(PF_CAN);






