From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3551978-1526433054-2-12062429048072682300 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no ("Email failed DMARC policy for domain") X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-IgnoreVacation: yes ("Email failed DMARC policy for domain") X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1526433054; b=GiEa+TwRsnk4B+c059Alsik7PZogVC8T0co6PJFM3B32ZlYl1S 5UEEtmB0mKxhLbV/mzKULnIlzZpmLjGO4pp6b95D0AuZEkf0OnKZtSy2IMhezWMr JhJVu+dlPE0WyOmEomGncUqk0QLVw5W4v1Fhe1IC6X1A156Q6SoBQxld6AKjFakC hXWV6xgkz48BWzi6Hk2dMKwSEq4vvtrPyOCVrMobRH7/FhH/UUw8XHtCALbSCQ/N iukXj1edpqiP4T6iCZmSbWwl90If6CegzwH17m73nnwAQvqrU4X4oj29QWeJ3iV7 0JWkM4f7dnAzr8n9jNDwRW3Hcz7GBXlAv+yQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=message-id:subject:from:to:cc:date :in-reply-to:references:content-type:mime-version :content-transfer-encoding:sender:list-id; s=fm2; t=1526433054; bh=/qEfQQd4U5ODW899aJJuVAonQHDKXVwXG5CrYBMuq+Q=; b=DSMQAYz03mi1 srX9WZ22JlWoRJDX8EARh1NZxNI8tWNSFxO+0lzYJRXncjec0kfA/NHm65TLh5Fy yPZ9o0A6SOQBDbxvpAYz45qgMA04fWpB2P9heUMmrp/7ikade1bgo1Xh8Y7jHs3A r070XBdTa2KG5pysBb+CVyDg9xry0p8HTllyJpyN1jaIRkED/M47IzCD2IGkeUSM SLeMmD3IZ2jyorTCnMbwFnHuUUPGGDz29jRVr9/KQIOqsBYvsLCeTFDOeCBK8j2b oedZLwfY3OAD4fJaXokJcajPTs8QwjwxjG12F+Qb4jmBCR/dc3Om3VCQYenuA1vt 4BAHCwEiGg== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=fail (p=none,has-list-id=yes,d=none) header.from=codethink.co.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=codethink.co.uk header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=fail (p=none,has-list-id=yes,d=none) header.from=codethink.co.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=codethink.co.uk header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfPCONzSov+5Gr6ejsM45D/GsyVyEECz/B3UFUrXJmtNPPjztMIbwAT8P4BUbQF23E9GIsjLvwYLao5MT3Wo5HU9f3Ro4o/E+whdcXIIX+4Azav2uJ03b ighRZxB/zzsxVgH3rm0rTfJsuZrSud3X5/ANBiCqGQunvpgE8gXVX7cdnVfH9FpnFM3B7zu/8jW4N4OISdqW7CC4xwd1tnrnQxjA10HTieQd59OYbeZCQNi9 X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=Byx-y9mGAAAA:8 a=USiETDfwkM-mFnYQSa4A:9 a=QEXdDO2ut3YA:10 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752024AbeEPBKv (ORCPT ); Tue, 15 May 2018 21:10:51 -0400 Received: from imap1.codethink.co.uk ([176.9.8.82]:59470 "EHLO imap1.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751853AbeEPBKv (ORCPT ); Tue, 15 May 2018 21:10:51 -0400 Message-ID: <1526433042.9159.103.camel@codethink.co.uk> Subject: Re: [PATCH 4.4 125/190] [media] cx25840: fix unchecked return values From: Ben Hutchings To: Pan Bian , Hans Verkuil , Mauro Carvalho Chehab Cc: stable@vger.kernel.org, Sasha Levin , Greg Kroah-Hartman , LKML Date: Wed, 16 May 2018 02:10:42 +0100 In-Reply-To: <20180411183559.391845365@linuxfoundation.org> References: <20180411183550.114495991@linuxfoundation.org> <20180411183559.391845365@linuxfoundation.org> Organization: Codethink Ltd. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, 2018-04-11 at 20:36 +0200, Greg Kroah-Hartman wrote: > 4.4-stable review patch.  If anyone has any objections, please let me know. > > ------------------ > > From: Pan Bian > > > [ Upstream commit 35378ce143071c2a6bad4b59a000e9b9f8f6ea67 ] > > In functions cx25840_initialize(), cx231xx_initialize(), and > cx23885_initialize(), the return value of create_singlethread_workqueue() > is used without validation. This may result in NULL dereference and cause > kernel crash. This patch fixes it. [...] > --- a/drivers/media/i2c/cx25840/cx25840-core.c > +++ b/drivers/media/i2c/cx25840/cx25840-core.c > @@ -420,11 +420,13 @@ static void cx25840_initialize(struct i2 >   INIT_WORK(&state->fw_work, cx25840_work_handler); >   init_waitqueue_head(&state->fw_wait); >   q = create_singlethread_workqueue("cx25840_fw"); > - prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE); > - queue_work(q, &state->fw_work); > - schedule(); > - finish_wait(&state->fw_wait, &wait); > - destroy_workqueue(q); > + if (q) { > + prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE); > + queue_work(q, &state->fw_work); > + schedule(); > + finish_wait(&state->fw_wait, &wait); > + destroy_workqueue(q); > + } [...] Why is the error "handled" by skipping part of the initialisation process? Shouldn't we abort and return an error? Why even create a private workqueue, when we don't do anything that wouldn't work with one of the global workqueues? Why even use a workqueue, if we immediately block waiting for the work to finish? This makes no sense to me. Ben. -- Ben Hutchings Software Developer, Codethink Ltd.