@@ -11,6 +11,7 @@
FN(SOCKET_INVALID_STATE) \
FN(SOCKET_RCVBUFF) \
FN(SOCKET_RCV_SHUTDOWN) \
+ FN(UNIX_DISCONNECT) \
FN(UNIX_INFLIGHT_FD_LIMIT) \
FN(UNIX_SKIP_OOB) \
FN(PKT_TOO_SMALL) \
@@ -152,6 +153,12 @@ enum skb_drop_reason {
SKB_DROP_REASON_SOCKET_RCVBUFF,
/** @SKB_DROP_REASON_SOCKET_RCV_SHUTDOWN: socket is shutdown(SHUT_RD) */
SKB_DROP_REASON_SOCKET_RCV_SHUTDOWN,
+ /**
+ * @SKB_DROP_REASON_UNIX_DISCONNECT: recv queue is purged when SOCK_DGRAM
+ * or SOCK_SEQPACKET socket re-connect()s to another socket or notices
+ * during send() that the peer has been close()d.
+ */
+ SKB_DROP_REASON_UNIX_DISCONNECT,
/**
* @SKB_DROP_REASON_UNIX_INFLIGHT_FD_LIMIT: too many file descriptors
* are passed via SCM_RIGHTS but not yet received, reaching RLIMIT_NOFILE.
@@ -622,7 +622,9 @@ static void unix_write_space(struct sock *sk)
static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
{
if (!skb_queue_empty(&sk->sk_receive_queue)) {
- skb_queue_purge(&sk->sk_receive_queue);
+ skb_queue_purge_reason(&sk->sk_receive_queue,
+ SKB_DROP_REASON_UNIX_DISCONNECT);
+
wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
/* If one link of bidirectional dgram pipe is disconnected,
unix_dgram_disconnected() is called from two places: 1. when a connect()ed socket disconnect() or re-connect()s to another socket 2. when sendmsg() fails because the peer socket that the client has connect()ed to has been close()d Then, the client's recv queue is purged to remove all messages from the old peer socket. Let's define a new drop reason for that case. # echo 1 > /sys/kernel/tracing/events/skb/kfree_skb/enable # python3 >>> from socket import * >>> >>> # s1 has a message from s2 >>> s1, s2 = socketpair(AF_UNIX, SOCK_DGRAM) >>> s2.send(b'hello world') >>> >>> # re-connect() drops the message from s2 >>> s3 = socket(AF_UNIX, SOCK_DGRAM) >>> s3.bind('') >>> s1.connect(s3.getsockname()) # cat /sys/kernel/tracing/trace_pipe python3-250 ... kfree_skb: ... location=skb_queue_purge_reason+0xdc/0x110 reason: UNIX_DISCONNECT Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> --- include/net/dropreason-core.h | 7 +++++++ net/unix/af_unix.c | 4 +++- 2 files changed, 10 insertions(+), 1 deletion(-)