From: Eric Dumazet <edumazet@google.com>
Date: Tue, 19 May 2026 19:32:48 +0000 (+0000)
Subject: ipv4: use WARN_ON_ONCE() in ip_rt_bug()
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e4bdef4d320b2fe73b8ebfc0cc0507fa9dc4a3b7;p=thirdparty%2Fkernel%2Flinux.git

ipv4: use WARN_ON_ONCE() in ip_rt_bug()

It turns out ip_rt_bug() can be called more than expected.

syzbot will still panic (because of panic_on_warn=1), but non debug
kernels will no longer die while repeating stack traces on the console.

Fixes: c378a9c019cf ("ipv4: Give backtrace in ip_rt_bug().")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://patch.msgid.link/20260519193248.4018872-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index bc1296f0ea69..3d62d45d84bd 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1272,7 +1272,7 @@ static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
 		 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
 		 skb->dev ? skb->dev->name : "?");
 	kfree_skb(skb);
-	WARN_ON(1);
+	WARN_ON_ONCE(1);
 	return 0;
 }