This is a note to let you know that I've just added the patch titled
net: Fix a data-race around sysctl_tstamp_allow_data.
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fix-a-data-race-around-sysctl_tstamp_allow_data.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f7abbc5629f5656940b9b9bbf6b08aefc10e3463
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Tue Aug 23 10:46:50 2022 -0700
net: Fix a data-race around sysctl_tstamp_allow_data.
[ 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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 22b216629f9bc..022e26c180241 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3905,7 +3905,7 @@ 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);
