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From:   Ren Mingshuai <renmingshuai@huawei.com>
To:     <kuba@kernel.org>
CC:     <caowangbao@huawei.com>, <davem@davemloft.net>,
        <khlebnikov@openvz.org>, <liaichun@huawei.com>,
        <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
        <oneukum@suse.com>, <renmingshuai@huawei.com>, <yanan@huawei.com>
Subject: Re: [PATCH] net: usbnet: Fix potential NULL pointer dereference
Date:   Thu, 2 Nov 2023 17:06:30 +0800
Message-ID: <20231102090630.938759-1-renmingshuai@huawei.com>
In-Reply-To: <20231101213832.77bd657b@kernel.org>
References: <20231101213832.77bd657b@kernel.org>
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>> >23ba07991dad said SKB can be NULL without describing the triggering 
>> >scenario. Always Check it before dereference to void potential NULL 
>> >pointer dereference.
>> I've tried to find out the scenarios where SKB is NULL, but failed.
>> It seems impossible for SKB to be NULL. If SKB can be NULL, please 
>> tell me the reason and I'd be very grateful.
>
>What do you mean? Grepping the function name shows call sites with NULL getting passed as skb.

Yes And I just learned that during the cdc_ncm_driver.probe, it is possible to pass a NULL SKB to usbnet_start_xmit().