[PATCH net v1] netmem: fix skb_frag_address_safe with unreadable skbs

[Mina Almasry]

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

Cc: ap420073@xxxxxxxxx

Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
---
 include/linux/skbuff.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5520524c93bf..9d551845e517 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3665,7 +3665,12 @@ 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));
+	void *ptr;
+
+	if (!skb_frag_page(frag))
+		return NULL;
+
+	ptr = page_address(skb_frag_page(frag));
 	if (unlikely(!ptr))
 		return NULL;
 

base-commit: 7b4ac12cc929e281cf7edc22203e0533790ebc2b
-- 
2.50.0.rc2.696.g1fc2a0284f-goog