From e850efcf2bb08a43a14da59a3ba43b5dd78c2d3f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 22 Sep 2023 22:03:53 +0000 Subject: [PATCH] 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 Reviewed-by: David Ahern Acked-by: Neal Cardwell Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- 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 99ac5efe244d..61c573a72db6 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 { -- 2.34.1