This is a note to let you know that I've just added the patch titled
igmp: Fix a data-race around sysctl_igmp_max_memberships.
to the 5.18-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:
igmp-fix-a-data-race-around-sysctl_igmp_max_membersh.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0f5f36fc7f4cd8086af89611acde3d35beee8e26
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Fri Jul 15 10:17:42 2022 -0700
igmp: Fix a data-race around sysctl_igmp_max_memberships.
[ Upstream commit 6305d821e3b9b5379d348528e5b5faf316383bc2 ]
While reading sysctl_igmp_max_memberships, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
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/ipv4/igmp.c b/net/ipv4/igmp.c
index 0bde3774505f..d07d290bf0b9 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -2197,7 +2197,7 @@ static int __ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr,
count++;
}
err = -ENOBUFS;
- if (count >= net->ipv4.sysctl_igmp_max_memberships)
+ if (count >= READ_ONCE(net->ipv4.sysctl_igmp_max_memberships))
goto done;
iml = sock_kmalloc(sk, sizeof(*iml), GFP_KERNEL);
if (!iml)
