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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: Davide Caratti <dcaratti@redhat.com>
Link: https://patch.msgid.link/20250604160605.1005704-3-dcaratti@redhat.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Davide Caratti 2025-06-04 18:06:05 +02:00 committed by Marc Kleine-Budde
parent 127c49624a
commit 81807451c2
4 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
net/can/bcm.c
View File

@ -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++;
}

5
net/can/isotp.c
View File

@ -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)

5
net/can/j1939/socket.c
View File

@ -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)

5
net/can/raw.c
View File

@ -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,