From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: usbnet: fix oops in usbnet_start_xmit Date: Thu, 06 Sep 2012 15:10:51 +0200 Message-ID: <25431888.4WZyYrK8zN@linux-lqwf.site> References: <20111109073459.GA14409@elgon.mountain> <20120906125230.GI19410@mwanda> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: khlebnikov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dan Carpenter Return-path: In-Reply-To: <20120906125230.GI19410@mwanda> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Thursday 06 September 2012 05:52:30 Dan Carpenter wrote: > I sent this email a year ago when the patch was committed but I > never received a response. I probably should have checked then. > regards, > dan carpenter > > On Wed, Nov 09, 2011 at 10:34:59AM +0300, Dan Carpenter wrote: > > Hello Konstantin Khlebnikov, > > > > This is a semi-automatic email about new static checker warnings. > > > > The patch 23ba07991dad: "usbnet: fix oops in usbnet_start_xmit" from > > Nov 7, 2011, leads to the following Smatch complaint: > > > > drivers/net/usb/usbnet.c +1077 usbnet_start_xmit() > > error: we previously assumed 'skb' could be null (see line 1060) > > > > drivers/net/usb/usbnet.c > > 1059 > > 1060 if (skb) > > ^^^ > > check introduced here. > > > > 1061 skb_tx_timestamp(skb); > > 1062 > > 1063 // some devices want funky USB-level framing, for > > 1064 // win32 driver (usually) and/or hardware quirks > > 1065 if (info->tx_fixup) { > > 1066 skb = info->tx_fixup (dev, skb, GFP_ATOMIC); It turns out that skb == NULL implies info->tx_fixup != NULL and skb will be reassigned. This is very dirty. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html