From: "Bjørn Mork" <bjorn@mork•no>
To: Vivek Kumar Bhagat <vivek.bhagat@samsung•com>
Cc: "netdev\@vger.kernel.org" <netdev@vger•kernel.org>,
Nitin Jhanwar <nitin.j@samsung•com>,
HEMANSHU SRIVASTAVA <hemanshu.s@samsung•com>
Subject: Re: [PATCH] usbnet: dereference after null check in usbnet_start_xmit() and __usbnet_read_cmd()
Date: Thu, 20 Aug 2015 09:29:05 +0200 [thread overview]
Message-ID: <87vbcacta6.fsf@nemi.mork.no> (raw)
In-Reply-To: <317402377.314001440045815822.JavaMail.weblogic@ep2mlwas02d> (Vivek Kumar Bhagat's message of "Thu, 20 Aug 2015 04:43:35 +0000 (GMT)")
Vivek Kumar Bhagat <vivek.bhagat@samsung•com> writes:
> Dear Bjorn,
>
>>>This is wrong. There are usbnet minidrivers depending on info->tx_fixup
>>> being called with a NULL skb.
> Also, if dev_hard_start_xmit() ensures that skb can not be NULL in usbnet_start_xmit()
> then we should remove below check.
> if (skb) <--- This check is confusing which says skb can be NULL.
> skb_tx_timestamp(skb);
No, that test is there because of the ugly hack in cdc_ncm. It doesn't
go through dev_hard_start_xmit(), but calls usbnet_start_xmit() directly
with a NULL skb as a signal to itself. Yes, I told you it was ugly ;)
I do agree that it would be nice to make this go away. But until that
happens usbnet_start_xmit() has to deal with NULL skbs, forwarding them
to the tx_fixup hook.
Bjørn
next prev parent reply other threads:[~2015-08-20 7:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-20 4:43 Re: [PATCH] usbnet: dereference after null check in usbnet_start_xmit() and __usbnet_read_cmd() Vivek Kumar Bhagat
2015-08-20 7:29 ` Bjørn Mork [this message]
-- strict thread matches above, loose matches on Subject: below --
2015-08-19 11:21 Vivek Kumar Bhagat
2015-08-19 11:51 ` Bjørn Mork
2015-08-19 12:03 ` Bjørn Mork
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