From: Jason Xing <kernelxing@tencent.com>
Date: Fri, 8 Mar 2024 11:25:04 +0000 (+0800)
Subject: tcp: annotate a data-race around sysctl_tcp_wmem[0]
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=683a67da95616c91a85b98e41dc8eefe9f2b29e7;p=linux.git

tcp: annotate a data-race around sysctl_tcp_wmem[0]

When reading wmem[0], it could be changed concurrently without
READ_ONCE() protection. So add one annotation here.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b091149742b1d..d20b62d521712 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -975,7 +975,7 @@ int tcp_wmem_schedule(struct sock *sk, int copy)
 	 * Use whatever is left in sk->sk_forward_alloc and tcp_wmem[0]
 	 * to guarantee some progress.
 	 */
-	left = sock_net(sk)->ipv4.sysctl_tcp_wmem[0] - sk->sk_wmem_queued;
+	left = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]) - sk->sk_wmem_queued;
 	if (left > 0)
 		sk_forced_mem_schedule(sk, min(left, copy));
 	return min(copy, sk->sk_forward_alloc);