On 10/2/21 2:37 AM, Cong Wang wrote:
From: Cong Wang <cong.wang@xxxxxxxxxxxxx>
Yucong noticed we can't poll() sockets in sockmap even
when they are the destination sockets of redirections.
This is because we never poll any psock queues in ->poll(),
except for TCP. With ->sock_is_readable() now we can
overwrite >sock_is_readable(), invoke and implement it for
both UDP and AF_UNIX sockets.
Reported-by: Yucong Sun <sunyucong@xxxxxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Cc: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
---
net/ipv4/udp.c | 2 ++
net/ipv4/udp_bpf.c | 1 +
net/unix/af_unix.c | 4 ++++
net/unix/unix_bpf.c | 2 ++
4 files changed, 9 insertions(+)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 2a7825a5b842..4a7e15a43a68 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2866,6 +2866,8 @@ __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
!(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)
mask &= ~(EPOLLIN | EPOLLRDNORM);
+ if (sk_is_readable(sk))
+ mask |= EPOLLIN | EPOLLRDNORM;
udp_poll() has this extra logic around first_packet_length() which drops all bad csum'ed
skbs. How does this stand in relation to sk_msg_is_readable()? Is this a concern as well
there? Maybe makes sense to elaborate a bit more in the commit message for context / future
reference.
Thanks,
Daniel
return mask;
}
