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

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Date:   Thu, 20 Apr 2017 16:03:43 -0700
From:   Greg Rose <gvrose8192@...il.com>
To:     Myungho Jung <mhjungk@...il.com>
Cc:     edumazet@...gle.com, netdev@...r.kernel.org
Subject: Re: [PATCH] p54: Prevent from dereferencing null pointer when
 releasing SKB

On Thu, 2017-04-20 at 11:25 -0700, Myungho Jung wrote:
> 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>

Hi,

I think the patch is fine but I'm confused by the subject.  You mention
p54 driver but the change is in dev.c.  I know the bugzilla references
the p54 but that's not where the change is.

Seems odd to me.

- Greg

> ---
>  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);