netdev - [PATCH net-next v2] netmem: fix skb_frag_address

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Message-ID: <20250619175239.3039329-1-almasrymina@google.com>
Date: Thu, 19 Jun 2025 17:52:38 +0000
From: Mina Almasry <almasrymina@...gle.com>
To: netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Mina Almasry <almasrymina@...gle.com>, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Simon Horman <horms@...nel.org>, ap420073@...il.com, Stanislav Fomichev <sdf@...ichev.me>
Subject: [PATCH net-next v2] netmem: fix skb_frag_address_safe with unreadable skbs

skb_frag_address_safe() needs a check that the
skb_frag_page exists check similar to skb_frag_address().

Cc: ap420073@...il.com

Signed-off-by: Mina Almasry <almasrymina@...gle.com>
Acked-by: Stanislav Fomichev <sdf@...ichev.me>

---

v2: https://lore.kernel.org/netdev/20250617210950.1338107-1-almasrymina@google.com/

- Move to net-next
- save return value of skb_frag_page
---
 include/linux/skbuff.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 9508968cb300..4f6dcb37bae8 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3665,7 +3665,13 @@ static inline void *skb_frag_address(const skb_frag_t *frag)
  */
 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
 {
-	void *ptr = page_address(skb_frag_page(frag));
+	struct page *page = skb_frag_page(frag);
+	void *ptr;
+
+	if (!page)
+		return NULL;
+
+	ptr = page_address(page);
 	if (unlikely(!ptr))
 		return NULL;
 

base-commit: afc783fa0aab9cc093fbb04871bfda406480cf8d
-- 
2.50.0.rc2.701.gf1e915cc24-goog