diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2025-07-21 19:20:21 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-22 18:21:15 -0700 |
| commit | 972ca7a3bc9a136b15ba698713b056a4900e2634 (patch) | |
| tree | 8ab2297a25df1d55c95e5d4a937605d8744cb164 /net/ipv4/tcp_input.c | |
| parent | 8839d1cc6ce0d38b4799380eae0c31bb0f07928b (diff) | |
tcp: do not set a zero size receive buffer
The nipa CI is reporting frequent failures in the mptcp_connect
self-tests.
In the failing scenarios (TCP -> MPTCP) the involved sockets are
actually plain TCP ones, as fallback for passive socket at 2whs
time cause the MPTCP listener to actually create a TCP socket.
The transfer is stuck due to the receiver buffer being zero.
With the stronger check in place, tcp_clamp_window() can be invoked
while the TCP socket has sk_rmem_alloc == 0, and the receive buffer
will be zeroed, too.
Check for the critical condition in tcp_prune_queue() and just
drop the packet without shrinking the receiver buffer.
Fixes: 1d2fbaad7cd8 ("tcp: stronger sk_rcvbuf checks")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20c18165d3f848e1c5c1b782d88c1a5ab38b3f70.1753118029.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 672cbfbdcec1..81b6d3770812 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5549,6 +5549,10 @@ static int tcp_prune_queue(struct sock *sk, const struct sk_buff *in_skb) { struct tcp_sock *tp = tcp_sk(sk); + /* Do nothing if our queues are empty. */ + if (!atomic_read(&sk->sk_rmem_alloc)) + return -1; + NET_INC_STATS(sock_net(sk), LINUX_MIB_PRUNECALLED); if (!tcp_can_ingest(sk, in_skb)) |