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From: Oliver Neukum <oneukum@suse.com>
To: "Ren Mingshuai" <renmingshuai@huawei.com>,
	kuba@kernel.org, "Bjørn Mork" <bjorn@mork.no>
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, yanan@huawei.com
Subject: Re: [PATCH] net: usbnet: Fix potential NULL pointer dereference
Date: Mon, 6 Nov 2023 13:59:08 +0100	[thread overview]
Message-ID: <b377a7c1-bf41-4fd2-81b9-ace2b6134c4e@suse.com> (raw)
In-Reply-To: <20231102090630.938759-1-renmingshuai@huawei.com>

On 02.11.23 10:06, Ren Mingshuai wrote:

>> What do you mean? Grepping the function name shows call sites with NULL getting passed as skb.

You may see that we do check skb != NULL before we timestamp it.
But later in the process we depend skb == NULL implying that tx_fixup != NULL

That is the combination that must not happen. If it happens, though
simply bailing out seems to the wrong answer.
  
> Yes And I just learned that during the cdc_ncm_driver.probe, it is possible to pass a NULL SKB to usbnet_start_xmit().

How can that happen? And if it happens is tx_fixup set?

	Regards
		Oliver


      parent reply	other threads:[~2023-11-06 12:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-01 12:35 Ren Mingshuai
2023-11-01 12:55 ` Ren Mingshuai
2023-11-02  4:38   ` Jakub Kicinski
2023-11-02  9:06     ` Ren Mingshuai
2023-11-06 10:18       ` Oliver Neukum
2023-11-06 10:55         ` Bjørn Mork
2023-11-06 12:53           ` Oliver Neukum
2023-11-06 12:59       ` Oliver Neukum [this message]

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