[PATCH 5.19 071/158] net: Fix a data-race around sysctl_tstamp_allow_data.

Greg Kroah-Hartman
2022-08-29T11:30:41Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit d2154b0afa73c0159b2856f875c6b4fe7cf6a95e ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 5b3559cb1d827..bebf58464d667 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4772,7 +4772,7 @@ 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);
--
2.35.1