diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-09-16 16:09:46 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-09-18 10:17:10 +0200 |
| commit | 9aaec660b5be29f23aaa7d1b0ae426b895dc0ca5 (patch) | |
| tree | 8a1dc03b8cdf6bd614cd88d5a7f92abdc83b0362 | |
| parent | b76543b21fbcfbb96332fd80cc0d85bbcd72d8f0 (diff) | |
udp: refine __udp_enqueue_schedule_skb() test
Commit 5a465a0da13e ("udp: Fix multiple wraparounds
of sk->sk_rmem_alloc.") allowed to slightly overshoot
sk->sk_rmem_alloc, when many cpus are trying
to feed packets to a common UDP socket.
This patch, combined with the following one reduces
false sharing on the victim socket under DDOS.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250916160951.541279-6-edumazet@google.com
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | net/ipv4/udp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index cca41c569f37..edd846fee90f 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1739,8 +1739,8 @@ int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb) if (rcvbuf > INT_MAX >> 1) goto drop; - /* Always allow at least one packet for small buffer. */ - if (rmem > rcvbuf) + /* Accept the packet if queue is empty. */ + if (rmem) goto drop; } |