This is a note to let you know that I've just added the patch titled
tcp_metrics: add missing barriers on delete
to the 4.19-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:
tcp_metrics-add-missing-barriers-on-delete.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b745a2db3e83526205a39c51409990dfc2a3a0a5
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Fri Sep 22 22:03:53 2023 +0000
tcp_metrics: add missing barriers on delete
[ Upstream commit cbc3a153222805d65f821e10f4f78b6afce06f86 ]
When removing an item from RCU protected list, we must prevent
store-tearing, using rcu_assign_pointer() or WRITE_ONCE().
Fixes: 04f721c671656 ("tcp_metrics: Rewrite tcp_metrics_flush_all")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Acked-by: Neal Cardwell <ncardwell@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 7bbd9125b5000..9ad4258cfcbcc 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -913,7 +913,7 @@ static void tcp_metrics_flush_all(struct net *net)
match = net ? net_eq(tm_net(tm), net) :
!refcount_read(&tm_net(tm)->count);
if (match) {
- *pp = tm->tcpm_next;
+ rcu_assign_pointer(*pp, tm->tcpm_next);
kfree_rcu(tm, rcu_head);
} else {
pp = &tm->tcpm_next;
@@ -954,7 +954,7 @@ static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
if (addr_same(&tm->tcpm_daddr, &daddr) &&
(!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
net_eq(tm_net(tm), net)) {
- *pp = tm->tcpm_next;
+ rcu_assign_pointer(*pp, tm->tcpm_next);
kfree_rcu(tm, rcu_head);
found = true;
} else {
