From: Kuniyuki Iwashima Date: Fri, 29 May 2026 19:39:23 +0000 (+0000) Subject: net: Annotate sk->sk_write_space() for UDP SOCKMAP. X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=b748765019fe9e9234660327090fc1a9665cdbdd;p=thirdparty%2Fkernel%2Flinux.git net: Annotate sk->sk_write_space() for UDP SOCKMAP. UDP TX skb->destructor() is sock_wfree(), and UDP holds lock_sock() only for UDP_CORK / MSG_MORE sendmsg(). Otherwise, sk->sk_write_space() may be read locklessly while SOCKMAP rewrites sk->sk_write_space(). Let's use WRITE_ONCE() and READ_ONCE() for sk->sk_write_space(). Note that the write side is annotated by commit 2ef2b20cf4e0 ("net: annotate data-races around sk->sk_{data_ready,write_space}"). Fixes: 7b98cd42b049 ("bpf: sockmap: Add UDP support") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jakub Sitnicki Link: https://patch.msgid.link/20260529193941.3897256-1-kuniyu@google.com Signed-off-by: Jakub Kicinski --- diff --git a/net/core/sock.c b/net/core/sock.c index b37b664b6eb9..d097025c116a 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2676,8 +2676,12 @@ void sock_wfree(struct sk_buff *skb) int old; if (!sock_flag(sk, SOCK_USE_WRITE_QUEUE)) { + void (*sk_write_space)(struct sock *sk); + + sk_write_space = READ_ONCE(sk->sk_write_space); + if (sock_flag(sk, SOCK_RCU_FREE) && - sk->sk_write_space == sock_def_write_space) { + sk_write_space == sock_def_write_space) { rcu_read_lock(); free = __refcount_sub_and_test(len, &sk->sk_wmem_alloc, &old); @@ -2693,7 +2697,7 @@ void sock_wfree(struct sk_buff *skb) * after sk_write_space() call */ WARN_ON(refcount_sub_and_test(len - 1, &sk->sk_wmem_alloc)); - sk->sk_write_space(sk); + sk_write_space(sk); len = 1; } /*