net: core: Prevent from dereferencing null pointer when releasing SKB

[ Upstream commit 9899886d5e8ec5b343b1efe44f185a0e68dc6454 ]

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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index ba7b812..7f2caad 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2355,6 +2355,9 @@ 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);