From 638632997c3173e41a7e5fb22d802d9bc0522fbf Mon Sep 17 00:00:00 2001 From: Talal Ahmad Date: Fri, 9 Jul 2021 11:43:06 -0400 Subject: [PATCH] tcp: call sk_wmem_schedule before sk_mem_charge in zerocopy path commit 358ed624207012f03318235017ac6fb41f8af592 upstream. sk_wmem_schedule makes sure that sk_forward_alloc has enough bytes for charging that is going to be done by sk_mem_charge. In the transmit zerocopy path, there is sk_mem_charge but there was no call to sk_wmem_schedule. This change adds that call. Without this call to sk_wmem_schedule, sk_forward_alloc can go negetive which is a bug because sk_forward_alloc is a per-socket space that has been forward charged so this can't be negative. Fixes: f214f915e7db ("tcp: enable MSG_ZEROCOPY") Signed-off-by: Talal Ahmad Reviewed-by: Willem de Bruijn Reviewed-by: Wei Wang Reviewed-by: Soheil Hassas Yeganeh Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2384ac048bea..54230852e5f9 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1361,6 +1361,9 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) } pfrag->offset += copy; } else { + if (!sk_wmem_schedule(sk, copy)) + goto wait_for_space; + err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg); if (err == -EMSGSIZE || err == -EEXIST) { tcp_mark_push(tp, skb);