Commit 81807451 authored by Davide Caratti's avatar Davide Caratti Committed by Marc Kleine-Budde
Browse files

can: add drop reasons in CAN protocols receive path 



sock_queue_rcv_skb() can fail because of lack of memory resources: use
drop reasons and pass the receiving socket to the tracepoint, so that
it's possible to better locate/debug such events.

Tested with:

| # modprobe vcan echo=1
| # ip link add name vcan2 type vcan
| # ip link set dev vcan2 up
| # ./netlayer/tst-proc 1 &
| # bg
| # while true ; do perf record -e skb:kfree_skb -aR  -- \
| > ./raw/tst-raw-sendto vcan2 ; perf script ; done
| [...]
| tst-raw-sendto 10942 [000] 506428.431856: skb:kfree_skb: skbaddr=0xffff97cec38b4200 rx_sk=0xffff97cf0f75a800 protocol=12 location=raw_rcv+0x20e reason: SOCKET_RCVBUF

Signed-off-by: default avatarDavide Caratti <dcaratti@redhat.com>
Link: https://patch.msgid.link/20250604160605.1005704-3-dcaratti@redhat.com


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 127c4962

net/can/bcm.c

+3 −2
Original line number Diff line number Diff line
@@ -359,6 +359,7 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head, 
	unsigned int datalen = head->nframes * op->cfsiz;

	int err;

	unsigned int *pflags;

	enum skb_drop_reason reason;



	skb = alloc_skb(sizeof(*head) + datalen, gfp_any());

	if (!skb)
@@ -413,11 +414,11 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head, 
	addr->can_family  = AF_CAN;

	addr->can_ifindex = op->rx_ifindex;



	err = sock_queue_rcv_skb(sk, skb);

	err = sock_queue_rcv_skb_reason(sk, skb, &reason);

	if (err < 0) {

		struct bcm_sock *bo = bcm_sk(sk);



		kfree_skb(skb);

		sk_skb_reason_drop(sk, skb, reason);

		/* don't care about overflows in this statistic */

		bo->dropped_usr_msgs++;

	}

net/can/isotp.c

+3 −2
Original line number Diff line number Diff line
@@ -278,6 +278,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus) 
static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)

{

	struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;

	enum skb_drop_reason reason;



	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
@@ -285,8 +286,8 @@ static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk) 
	addr->can_family = AF_CAN;

	addr->can_ifindex = skb->dev->ifindex;



	if (sock_queue_rcv_skb(sk, skb) < 0)

		kfree_skb(skb);

	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0)

		sk_skb_reason_drop(sk, skb, reason);

}



static u8 padlen(u8 datalen)

net/can/j1939/socket.c

+3 −2
Original line number Diff line number Diff line
@@ -311,6 +311,7 @@ static void j1939_sk_recv_one(struct j1939_sock *jsk, struct sk_buff *oskb) 
{

	const struct j1939_sk_buff_cb *oskcb = j1939_skb_to_cb(oskb);

	struct j1939_sk_buff_cb *skcb;

	enum skb_drop_reason reason;

	struct sk_buff *skb;



	if (oskb->sk == &jsk->sk)
@@ -331,8 +332,8 @@ static void j1939_sk_recv_one(struct j1939_sock *jsk, struct sk_buff *oskb) 
	if (skb->sk)

		skcb->msg_flags |= MSG_DONTROUTE;



	if (sock_queue_rcv_skb(&jsk->sk, skb) < 0)

		kfree_skb(skb);

	if (sock_queue_rcv_skb_reason(&jsk->sk, skb, &reason) < 0)

		sk_skb_reason_drop(&jsk->sk, skb, reason);

}



bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)

net/can/raw.c

+3 −2
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data) 
{

	struct sock *sk = (struct sock *)data;

	struct raw_sock *ro = raw_sk(sk);

	enum skb_drop_reason reason;

	struct sockaddr_can *addr;

	struct sk_buff *skb;

	unsigned int *pflags;
@@ -205,8 +206,8 @@ static void raw_rcv(struct sk_buff *oskb, void *data) 
	if (oskb->sk == sk)

		*pflags |= MSG_CONFIRM;



	if (sock_queue_rcv_skb(sk, skb) < 0)

		kfree_skb(skb);

	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0)

		sk_skb_reason_drop(sk, skb, reason);

}



static int raw_enable_filters(struct net *net, struct net_device *dev,