[PATCH net-next 7/7] can: add drop reasons in CAN protocols receive path
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: 2025-06-10 09:49:41
Also in:
linux-can
Subsystem:
can network layer, can-j1939 network layer, the rest · Maintainers:
Oliver Hartkopp, Marc Kleine-Budde, Robin van der Gracht, Oleksij Rempel, Linus Torvalds
From: Davide Caratti <redacted> 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: Davide Caratti <redacted> Link: https://patch.msgid.link/20250604160605.1005704-3-dcaratti@redhat.com Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> --- net/can/bcm.c | 5 +++-- net/can/isotp.c | 5 +++-- net/can/j1939/socket.c | 5 +++-- net/can/raw.c | 5 +++-- 4 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 6bc1cc4c94c5..5e690a2377e4 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c@@ -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++; }
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 1efa377f002e..dee1412b3c9c 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c@@ -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)
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index 6fefe7a68761..3d8b588822f9 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c@@ -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)
diff --git a/net/can/raw.c b/net/can/raw.c
index 020f21430b1d..76b867d21def 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c@@ -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,
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2.47.2