5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ 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>
---
net/ipv4/tcp_metrics.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 5df97aaac252e..0275bf7570b4c 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -908,7 +908,7 @@ static void tcp_metrics_flush_all(struct net *net)
match = net ? net_eq(tm_net(tm), net) :
!refcount_read(&tm_net(tm)->ns.count);
if (match) {
- *pp = tm->tcpm_next;
+ rcu_assign_pointer(*pp, tm->tcpm_next);
kfree_rcu(tm, rcu_head);
} else {
pp = &tm->tcpm_next;
@@ -949,7 +949,7 @@ 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 {
--
2.42.0
