This is a note to let you know that I've just added the patch titled
net: Fix a data-race around sysctl_net_busy_poll.
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_net_busy_poll.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 6903e1ff67c5efd3523e40fb62abac493083d38b
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Tue Aug 23 10:46:51 2022 -0700
net: Fix a data-race around sysctl_net_busy_poll.
[ Upstream commit c42b7cddea47503411bfb5f2f93a4154aaffa2d9 ]
While reading sysctl_net_busy_poll, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 060212928670 ("net: add low latency socket poll")
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/include/net/busy_poll.h b/include/net/busy_poll.h
index 2fbeb1313c0f4..e522187cb6935 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -39,7 +39,7 @@ extern unsigned int sysctl_net_busy_poll __read_mostly;
static inline bool net_busy_loop_on(void)
{
- return sysctl_net_busy_poll;
+ return READ_ONCE(sysctl_net_busy_poll);
}
static inline u64 busy_loop_us_clock(void)
