[PATCH 5.4 37/84] net: mark racy access on sk->sk_rcvbuf

Greg Kroah-Hartman
2024-05-14T11:45:11Z

From: linke li <lilinke99@qq.com>

[ Upstream commit c2deb2e971f5d9aca941ef13ee05566979e337a4 ]

sk->sk_rcvbuf in __sock_queue_rcv_skb() and __sk_receive_skb() can be
changed by other threads. Mark this as benign using READ_ONCE().

This patch is aimed at reducing the number of benign races reported by
KCSAN in order to focus future debugging effort on harmful races.

Signed-off-by: linke li <lilinke99@qq.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/sock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index daeb0e69c71b4..2b68a93adfa8d 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -453,7 +453,7 @@ int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
unsigned long flags;
struct sk_buff_head *list = &sk->sk_receive_queue;

- if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) {
+ if (atomic_read(&sk->sk_rmem_alloc) >= READ_ONCE(sk->sk_rcvbuf)) {
atomic_inc(&sk->sk_drops);
trace_sock_rcvqueue_full(sk, skb);
return -ENOMEM;
@@ -505,7 +505,7 @@ int __sk_receive_skb(struct sock *sk, struct sk_buff *skb,

skb->dev = NULL;

- if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
+ if (sk_rcvqueues_full(sk, READ_ONCE(sk->sk_rcvbuf))) {
atomic_inc(&sk->sk_drops);
goto discard_and_relse;
}
--
2.43.0