This is a note to let you know that I've just added the patch titled
bpf, sockmap: Wake up polling after data copy
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-sockmap-wake-up-polling-after-data-copy.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 345ad8e80d4dd3f71799f527f3eabb77d9429e2a
Author: John Fastabend <john.fastabend@xxxxxxxxx>
Date: Mon May 22 19:56:11 2023 -0700
bpf, sockmap: Wake up polling after data copy
[ Upstream commit 6df7f764cd3cf5a03a4a47b23be47e57e41fcd85 ]
When TCP stack has data ready to read sk_data_ready() is called. Sockmap
overwrites this with its own handler to call into BPF verdict program.
But, the original TCP socket had sock_def_readable that would additionally
wake up any user space waiters with sk_wake_async().
Sockmap saved the callback when the socket was created so call the saved
data ready callback and then we can wake up any epoll() logic waiting
on the read.
Note we call on 'copied >= 0' to account for returning 0 when a FIN is
received because we need to wake up user for this as well so they
can do the recvmsg() -> 0 and detect the shutdown.
Fixes: 04919bed948dc ("tcp: Introduce tcp_read_skb()")
Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Reviewed-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20230523025618.113937-8-john.fastabend@xxxxxxxxx
Stable-dep-of: 6648e613226e ("bpf, skmsg: Fix NULL pointer dereference in sk_psock_skb_ingress_enqueue")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 68418954ac492..75554adef5df9 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -1213,10 +1213,19 @@ static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb)
static void sk_psock_verdict_data_ready(struct sock *sk)
{
struct socket *sock = sk->sk_socket;
+ int copied;
if (unlikely(!sock || !sock->ops || !sock->ops->read_skb))
return;
- sock->ops->read_skb(sk, sk_psock_verdict_recv);
+ copied = sock->ops->read_skb(sk, sk_psock_verdict_recv);
+ if (copied >= 0) {
+ struct sk_psock *psock;
+
+ rcu_read_lock();
+ psock = sk_psock(sk);
+ psock->saved_data_ready(sk);
+ rcu_read_unlock();
+ }
}
void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
