From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9208FC43381 for ; Tue, 19 Mar 2019 13:56:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60FA3213F2 for ; Tue, 19 Mar 2019 13:56:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553003774; bh=8t8/3Cwy38Eu38/Is7aZyv/pQQNZSsCulps/l3FJCok=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=psZUMEWGUC+UG9Vhwo98JVWZIkXciSgfy1lP5zP1oTfQBOHdP3rf/BLuUxWZOXNww swcAof7UY3tljLiDmUXspOQbT7ltkygA4lzp5bKkBHjLmqHYf+kliFf5b9gQV3fU0n QdaEWf0znlNCrnl0U7i8M1uYAmwTExpfUmJmOvLk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727368AbfCSN4M (ORCPT ); Tue, 19 Mar 2019 09:56:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:60780 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726464AbfCSN4M (ORCPT ); Tue, 19 Mar 2019 09:56:12 -0400 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 74BDA2085A; Tue, 19 Mar 2019 13:56:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553003772; bh=8t8/3Cwy38Eu38/Is7aZyv/pQQNZSsCulps/l3FJCok=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OBSi7nmTh2q5l7s/1GdaO7rNHZNBWCNV5wUsVTe2jm59Z2d7iPaJpXWcYfh/cGxOQ uLBLYco6dlajZ21bDIrrLBNhLi1ZBBwDFEEjISUZHWRHHJPPIXwKrqDn+cX78IyrpB dsFTkck6YR73YMbTEtLMSTNE9FKBXNAr1V+U7jtg= Date: Tue, 19 Mar 2019 14:56:09 +0100 From: Greg Kroah-Hartman To: Kangjie Lu Cc: pakki001@umn.edu, Colin Ian King , Jia-Ju Bai , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: u132-hcd: fix potential NULL pointer dereference Message-ID: <20190319135609.GA16254@kroah.com> References: <20190314072713.20666-1-kjlu@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190314072713.20666-1-kjlu@umn.edu> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 14, 2019 at 02:27:11AM -0500, Kangjie Lu wrote: > In case create_singlethread_workqueue fails, the fix notifies > callers the error to avoid potential NULL pointer dereferences. > > Signed-off-by: Kangjie Lu > --- > drivers/usb/host/u132-hcd.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/usb/host/u132-hcd.c b/drivers/usb/host/u132-hcd.c > index 934584f0a20a..6d5b532b03f8 100644 > --- a/drivers/usb/host/u132-hcd.c > +++ b/drivers/usb/host/u132-hcd.c > @@ -3203,6 +3203,8 @@ static int __init u132_hcd_init(void) > return -ENODEV; > printk(KERN_INFO "driver %s\n", hcd_name); > workqueue = create_singlethread_workqueue("u132"); > + if (unlikely(!workqueue)) You only ever use unlikely/likely if you can actually measure the difference with and without it. For stuff like this, it is not needed at all, and in fact, the compiler and CPU already know this type of thing, so it is going to be faster without it. And are you sure you properly unwound from anything that was created/initialized above these lines? thanks, greg k-h From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: usb: u132-hcd: fix potential NULL pointer dereference From: Greg Kroah-Hartman Message-Id: <20190319135609.GA16254@kroah.com> Date: Tue, 19 Mar 2019 14:56:09 +0100 To: Kangjie Lu Cc: pakki001@umn.edu, Colin Ian King , Jia-Ju Bai , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: T24gVGh1LCBNYXIgMTQsIDIwMTkgYXQgMDI6Mjc6MTFBTSAtMDUwMCwgS2FuZ2ppZSBMdSB3cm90 ZToKPiBJbiBjYXNlIGNyZWF0ZV9zaW5nbGV0aHJlYWRfd29ya3F1ZXVlIGZhaWxzLCB0aGUgZml4 IG5vdGlmaWVzCj4gY2FsbGVycyB0aGUgZXJyb3IgdG8gYXZvaWQgcG90ZW50aWFsIE5VTEwgcG9p bnRlciBkZXJlZmVyZW5jZXMuCj4gCj4gU2lnbmVkLW9mZi1ieTogS2FuZ2ppZSBMdSA8a2psdUB1 bW4uZWR1Pgo+IC0tLQo+ICBkcml2ZXJzL3VzYi9ob3N0L3UxMzItaGNkLmMgfCAyICsrCj4gIDEg ZmlsZSBjaGFuZ2VkLCAyIGluc2VydGlvbnMoKykKPiAKPiBkaWZmIC0tZ2l0IGEvZHJpdmVycy91 c2IvaG9zdC91MTMyLWhjZC5jIGIvZHJpdmVycy91c2IvaG9zdC91MTMyLWhjZC5jCj4gaW5kZXgg OTM0NTg0ZjBhMjBhLi42ZDViNTMyYjAzZjggMTAwNjQ0Cj4gLS0tIGEvZHJpdmVycy91c2IvaG9z dC91MTMyLWhjZC5jCj4gKysrIGIvZHJpdmVycy91c2IvaG9zdC91MTMyLWhjZC5jCj4gQEAgLTMy MDMsNiArMzIwMyw4IEBAIHN0YXRpYyBpbnQgX19pbml0IHUxMzJfaGNkX2luaXQodm9pZCkKPiAg CQlyZXR1cm4gLUVOT0RFVjsKPiAgCXByaW50ayhLRVJOX0lORk8gImRyaXZlciAlc1xuIiwgaGNk X25hbWUpOwo+ICAJd29ya3F1ZXVlID0gY3JlYXRlX3NpbmdsZXRocmVhZF93b3JrcXVldWUoInUx MzIiKTsKPiArCWlmICh1bmxpa2VseSghd29ya3F1ZXVlKSkKCllvdSBvbmx5IGV2ZXIgdXNlIHVu bGlrZWx5L2xpa2VseSBpZiB5b3UgY2FuIGFjdHVhbGx5IG1lYXN1cmUgdGhlCmRpZmZlcmVuY2Ug d2l0aCBhbmQgd2l0aG91dCBpdC4gIEZvciBzdHVmZiBsaWtlIHRoaXMsIGl0IGlzIG5vdCBuZWVk ZWQKYXQgYWxsLCBhbmQgaW4gZmFjdCwgdGhlIGNvbXBpbGVyIGFuZCBDUFUgYWxyZWFkeSBrbm93 IHRoaXMgdHlwZSBvZgp0aGluZywgc28gaXQgaXMgZ29pbmcgdG8gYmUgZmFzdGVyIHdpdGhvdXQg aXQuCgpBbmQgYXJlIHlvdSBzdXJlIHlvdSBwcm9wZXJseSB1bndvdW5kIGZyb20gYW55dGhpbmcg dGhhdCB3YXMKY3JlYXRlZC9pbml0aWFsaXplZCBhYm92ZSB0aGVzZSBsaW5lcz8KCnRoYW5rcywK CmdyZWcgay1oCg==