From cf28ff8e4c02e1ffa850755288ac954b6ff0db8c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 31 May 2024 13:26:35 +0000 Subject: [PATCH] ila: block BH in ila_output() As explained in commit 1378817486d6 ("tipc: block BH before using dst_cache"), net/core/dst_cache.c helpers need to be called with BH disabled. ila_output() is called from lwtunnel_output() possibly from process context, and under rcu_read_lock(). We might be interrupted by a softirq, re-enter ila_output() and corrupt dst_cache data structures. Fix the race by using local_bh_disable(). Signed-off-by: Eric Dumazet Acked-by: Paolo Abeni Link: https://lore.kernel.org/r/20240531132636.2637995-5-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/ipv6/ila/ila_lwt.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/ipv6/ila/ila_lwt.c b/net/ipv6/ila/ila_lwt.c index 0601bad79822..ff7e734e335b 100644 --- a/net/ipv6/ila/ila_lwt.c +++ b/net/ipv6/ila/ila_lwt.c @@ -58,7 +58,9 @@ static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb) return orig_dst->lwtstate->orig_output(net, sk, skb); } + local_bh_disable(); dst = dst_cache_get(&ilwt->dst_cache); + local_bh_enable(); if (unlikely(!dst)) { struct ipv6hdr *ip6h = ipv6_hdr(skb); struct flowi6 fl6; @@ -86,8 +88,11 @@ static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb) goto drop; } - if (ilwt->connected) + if (ilwt->connected) { + local_bh_disable(); dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr); + local_bh_enable(); + } } skb_dst_set(skb, dst); -- 2.20.1