From: Eric Dumazet <edumazet@google.com>
Date: Fri, 30 Jan 2026 16:02:53 +0000 (+0000)
Subject: net: add a debug check in __skb_push()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc9fd14bd75967d039262d73189fdd123edc5dce;p=thirdparty%2Fkernel%2Flinux.git

net: add a debug check in __skb_push()

Add the following check, to detect bugs sooner for CONFIG_DEBUG_NET=y
builds.

	DEBUG_NET_WARN_ON_ONCE(skb->data < skb->head);

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260130160253.2936789-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index e6bfe5d0c525..8b399ddf1b9b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2813,6 +2813,7 @@ static inline void *__skb_push(struct sk_buff *skb, unsigned int len)
 	DEBUG_NET_WARN_ON_ONCE(len > INT_MAX);
 
 	skb->data -= len;
+	DEBUG_NET_WARN_ON_ONCE(skb->data < skb->head);
 	skb->len  += len;
 	return skb->data;
 }