[PATCH v4 net 07/17] net: Fix a data-race around sysctl_tstamp_allow_data.

[Kuniyuki Iwashima <kuniyu@amazon.com>]

While reading sysctl_tstamp_allow_data, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: b245be1f4db1 ("net-timestamp: no-payload only sysctl")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Willem de Bruijn <willemb@google.com>
---
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 974bbbbe7138..174f34124c06 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4798,7 +4798,7 @@ static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
 {
 	bool ret;
 
-	if (likely(sysctl_tstamp_allow_data || tsonly))
+	if (likely(READ_ONCE(sysctl_tstamp_allow_data) || tsonly))
 		return true;
 
 	read_lock_bh(&sk->sk_callback_lock);
-- 
2.30.2