diff options
| author | Hangyu Hua | 2022-07-29 19:00:27 +0800 |
|---|---|---|
| committer | Jakub Kicinski | 2022-08-01 12:11:56 -0700 |
| commit | a41b17ff9dacd22f5f118ee53d82da0f3e52d5e3 (patch) | |
| tree | 6197eb604669c4bfd619422b6ea9c78ef3cd6f95 /net | |
| parent | 1e02fd7671fe8ef64866e7753659c635192f5061 (diff) | |
dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock
In the case of sk->dccps_qpolicy == DCCPQ_POLICY_PRIO, dccp_qpolicy_full
will drop a skb when qpolicy is full. And the lock in dccp_sendmsg is
released before sock_alloc_send_skb and then relocked after
sock_alloc_send_skb. The following conditions may lead dccp_qpolicy_push
to add skb to an already full sk_write_queue:
thread1--->lock
thread1--->dccp_qpolicy_full: queue is full. drop a skb
thread1--->unlock
thread2--->lock
thread2--->dccp_qpolicy_full: queue is not full. no need to drop.
thread2--->unlock
thread1--->lock
thread1--->dccp_qpolicy_push: add a skb. queue is full.
thread1--->unlock
thread2--->lock
thread2--->dccp_qpolicy_push: add a skb!
thread2--->unlock
Fix this by moving dccp_qpolicy_full.
Fixes: b1308dc015eb ("[DCCP]: Set TX Queue Length Bounds via Sysctl")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20220729110027.40569-1-hbh25y@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/dccp/proto.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/net/dccp/proto.c b/net/dccp/proto.c index eb8e128e43e8..e13641c65f88 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -736,11 +736,6 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) lock_sock(sk); - if (dccp_qpolicy_full(sk)) { - rc = -EAGAIN; - goto out_release; - } - timeo = sock_sndtimeo(sk, noblock); /* @@ -759,6 +754,11 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (skb == NULL) goto out_release; + if (dccp_qpolicy_full(sk)) { + rc = -EAGAIN; + goto out_discard; + } + if (sk->sk_state == DCCP_CLOSED) { rc = -ENOTCONN; goto out_discard; |