[PATCH v2] net: mark racy access on sk->sk_rcvbuf

[PATCH v2] net: mark racy access on sk->sk_rcvbuf

[linke li]

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>
---
v1 -> v2: include sk->sk_rcvbuf in __sock_queue_rcv_skb()

 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 5e78798456fd..61c14623a218 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -481,7 +481,7 @@ 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;
@@ -551,7 +551,7 @@ 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;
 	}
-- 
2.39.3 (Apple Git-146)

Re: [PATCH v2] net: mark racy access on sk->sk_rcvbuf

[Eric Dumazet]

On Thu, Mar 21, 2024 at 9:44 AM linke li <lilinke99@qq.com> wrote:
>
> 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>
> ---
> v1 -> v2: include sk->sk_rcvbuf in __sock_queue_rcv_skb()

Reviewed-by: Eric Dumazet <edumazet@google.com>

Re: [PATCH v2] net: mark racy access on sk->sk_rcvbuf

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Thu, 21 Mar 2024 16:44:10 +0800 you wrote:
> 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>
> 
> [...]

Here is the summary with links:
  - [v2] net: mark racy access on sk->sk_rcvbuf
    https://git.kernel.org/netdev/net/c/c2deb2e971f5

You are awesome, thank you!
-- 
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