netdev - [PATCH] p54: Prevent from dereferencing null pointer when releasing SKB

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Message-Id: <1491863998-15131-1-git-send-email-mhjungk@gmail.com>
Date:   Mon, 10 Apr 2017 15:39:58 -0700
From:   Myungho Jung <mhjungk@...il.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, chunkeey@...glemail.com,
        Myungho Jung <mhjungk@...il.com>
Subject: [PATCH] p54: Prevent from dereferencing null pointer when releasing SKB

Added NULL check to make __dev_kfree_skb_irq consistent with kfree
family of functions.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=195289

Signed-off-by: Myungho Jung <mhjungk@...il.com>
---
 net/core/dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index 7869ae3..22be2a6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2450,6 +2450,9 @@ void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
 {
 	unsigned long flags;
 
+	if (unlikely(!skb))
+		return;
+
 	if (likely(atomic_read(&skb->users) == 1)) {
 		smp_rmb();
 		atomic_set(&skb->users, 0);
-- 
2.7.4