From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751764AbbCVHpI (ORCPT ); Sun, 22 Mar 2015 03:45:08 -0400 Received: from mail-bn1bn0109.outbound.protection.outlook.com ([157.56.110.109]:47172 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751583AbbCVHpF (ORCPT ); Sun, 22 Mar 2015 03:45:05 -0400 Date: Sun, 22 Mar 2015 15:43:54 +0800 From: Peter Chen To: Badhri Jagan Sridharan CC: Felipe Balbi , Greg Kroah-Hartman , , Subject: Re: [PATCH] usb: gadget: Check for NULL pointer in disconnect Message-ID: <20150322074353.GA25278@shlinux2> References: <1426894852-4256-1-git-send-email-Badhri@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1426894852-4256-1-git-send-email-Badhri@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-EOPAttributedMessage: 0 Authentication-Results: spf=fail (sender IP is 192.88.168.50) smtp.mailfrom=peter.chen@freescale.com; vger.kernel.org; dkim=none (message not signed) header.d=none; X-Forefront-Antispam-Report: CIP:192.88.168.50;CTRY:US;IPV:NLI;EFV:NLI;BMV:1;SFV:NSPM;SFS:(10019020)(6009001)(339900001)(24454002)(189002)(199003)(51704005)(110136001)(33716001)(105606002)(106466001)(46102003)(77096005)(104016003)(6806004)(76176999)(33656002)(54356999)(23726002)(50986999)(92566002)(87936001)(86362001)(15975445007)(47776003)(97756001)(19580395003)(19580405001)(83506001)(62966003)(2950100001)(50466002)(77156002)(46406003)(61793002);DIR:OUT;SFP:1102;SCL:1;SRVR:DM2PR0301MB0638;H:tx30smr01.am.freescale.net;FPR:;SPF:Fail;MLV:sfv;MX:1;A:1;LANG:en; X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:DM2PR0301MB0638; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(5002010)(5005006);SRVR:DM2PR0301MB0638;BCL:0;PCL:0;RULEID:;SRVR:DM2PR0301MB0638; X-Forefront-PRVS: 0523CF0711 X-OriginatorOrg: freescale.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Mar 2015 07:45:01.7744 (UTC) X-MS-Exchange-CrossTenant-Id: 710a03f5-10f6-4d38-9ff4-a80b81da590d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=710a03f5-10f6-4d38-9ff4-a80b81da590d;Ip=[192.88.168.50];Helo=[tx30smr01.am.freescale.net] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM2PR0301MB0638 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 20, 2015 at 04:40:52PM -0700, Badhri Jagan Sridharan wrote: > Added a safety net to make sure that > composite_disconnect does not end up disconneting > a NULL device. Prevents NULL pointer crash. > > Signed-off-by: Badhri Jagan Sridharan > --- > drivers/usb/gadget/composite.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c > index 13adfd1..90b37bd 100644 > --- a/drivers/usb/gadget/composite.c > +++ b/drivers/usb/gadget/composite.c > @@ -1823,6 +1823,11 @@ void composite_disconnect(struct usb_gadget *gadget) > struct usb_composite_dev *cdev = get_gadget_data(gadget); > unsigned long flags; > > + if (!cdev) { > + WARN(1, "Trying to disconnect a NULL composite device\n"); > + return; > + } > + Do you really see some udc drivers call it after composite_unbind is called? If it is, you may add dump_stack() to track that error. Besides this, function suspended_show is needed to add cdev NULL pointer checking. > /* REVISIT: should we have config and device level > * disconnect callbacks? > */ > -- > 2.2.0.rc0.207.ga3a616c > > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Best Regards, Peter Chen