diff mbox series

[v2,net-next,03/10] tcp: sk->sk_bound_dev_if once in inet_request_bound_dev_if()

Message ID 20220513185550.844558-4-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit fdb5fd7f736ec7ae9fb36d2842ea6d9ebc4e7269
Delegated to: Netdev Maintainers
Headers show
Series [v2,net-next,01/10] net: annotate races around sk->sk_bound_dev_if | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2323 this patch: 2323
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 587 this patch: 587
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2453 this patch: 2453
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet May 13, 2022, 6:55 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

inet_request_bound_dev_if() reads sk->sk_bound_dev_if twice
while listener socket is not locked.

Another cpu could change this field under us.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/inet_sock.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 234d70ae5f4cbdc3b2caaf10df81495439a101a5..c1b5dcd6597c622dfea3d4a646f97c87acb7ea32 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -116,14 +116,15 @@  static inline u32 inet_request_mark(const struct sock *sk, struct sk_buff *skb)
 static inline int inet_request_bound_dev_if(const struct sock *sk,
 					    struct sk_buff *skb)
 {
+	int bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
 #ifdef CONFIG_NET_L3_MASTER_DEV
 	struct net *net = sock_net(sk);
 
-	if (!sk->sk_bound_dev_if && net->ipv4.sysctl_tcp_l3mdev_accept)
+	if (!bound_dev_if && net->ipv4.sysctl_tcp_l3mdev_accept)
 		return l3mdev_master_ifindex_by_index(net, skb->skb_iif);
 #endif
 
-	return sk->sk_bound_dev_if;
+	return bound_dev_if;
 }
 
 static inline int inet_sk_bound_l3mdev(const struct sock *sk)