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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E93D5C433E0 for ; Fri, 5 Mar 2021 17:25:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4FFA650A5 for ; Fri, 5 Mar 2021 17:25:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229551AbhCERYb (ORCPT ); Fri, 5 Mar 2021 12:24:31 -0500 Received: from m42-2.mailgun.net ([69.72.42.2]:35945 "EHLO m42-2.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229493AbhCERYU (ORCPT ); Fri, 5 Mar 2021 12:24:20 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1614965060; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=4NIisY4w811oIA/VcR62rR+yydbAx2ISOLfSurqEVg8=; b=iYmezbiEGkphh+tI362GvzDEo+jAimPDMMIOpC/RoFPpxToUyPFLRFBULSKX9d4S53aKOzEK 1JOvFB/C3SylDamkc6YGhe2dmhEPC2xvN4wJX3XmOxPZxzMlr9uDgRgA/LYnneyJxyx/lFpG WTB3AgiV3iEgYupPbP9nE10dowE= X-Mailgun-Sending-Ip: 69.72.42.2 X-Mailgun-Sid: WyI5ZDFmMiIsICJsaW51eC1wbUB2Z2VyLmtlcm5lbC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n01.prod.us-east-1.postgun.com with SMTP id 604269351a5c93533f2f7fce (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 05 Mar 2021 17:24:05 GMT Sender: manafm=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id E4088C43461; Fri, 5 Mar 2021 17:24:04 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: manafm) by smtp.codeaurora.org (Postfix) with ESMTPSA id 2A61EC433CA; Fri, 5 Mar 2021 17:24:04 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 05 Mar 2021 22:54:04 +0530 From: manafm@codeaurora.org To: Zhang Rui , Eduardo Valentin , Daniel Lezcano , Amit Kucheria , Ram Chandrasekar Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] drivers: thermal: Add NULL pointer check before using cooling device stats In-Reply-To: <1607367181-24589-1-git-send-email-manafm@codeaurora.org> References: <1607367181-24589-1-git-send-email-manafm@codeaurora.org> Message-ID: <483eabf92d011964d58c2321c9344ed2@codeaurora.org> X-Sender: manafm@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 2020-12-08 00:23, Manaf Meethalavalappu Pallikunhi wrote: Gentle reminder.. > There is a possible chance that some cooling device stats buffer > allocation fails due to very high cooling device max state value. > Later cooling device update sysfs can try to access stats data > for the same cooling device. It will lead to NULL pointer > dereference issue. > > Add a NULL pointer check before accessing thermal cooling device > stats data. It fixes the following bug > > [ 26.812833] Unable to handle kernel NULL pointer dereference at > virtual address 0000000000000004 > [ 27.122960] Call trace: > [ 27.122963] do_raw_spin_lock+0x18/0xe8 > [ 27.122966] _raw_spin_lock+0x24/0x30 > [ 27.128157] thermal_cooling_device_stats_update+0x24/0x98 > [ 27.128162] cur_state_store+0x88/0xb8 > [ 27.128166] dev_attr_store+0x40/0x58 > [ 27.128169] sysfs_kf_write+0x50/0x68 > [ 27.133358] kernfs_fop_write+0x12c/0x1c8 > [ 27.133362] __vfs_write+0x54/0x160 > [ 27.152297] vfs_write+0xcc/0x188 > [ 27.157132] ksys_write+0x78/0x108 > [ 27.162050] ksys_write+0xf8/0x108 > [ 27.166968] __arm_smccc_hvc+0x158/0x4b0 > [ 27.166973] __arm_smccc_hvc+0x9c/0x4b0 > [ 27.186005] el0_svc+0x8/0xc > > Signed-off-by: Manaf Meethalavalappu Pallikunhi > --- > drivers/thermal/thermal_sysfs.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/thermal/thermal_sysfs.c > b/drivers/thermal/thermal_sysfs.c > index 473449b..10ca4f5 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -827,6 +827,9 @@ void thermal_cooling_device_stats_update(struct > thermal_cooling_device *cdev, > { > struct cooling_dev_stats *stats = cdev->stats; > > + if (!stats) > + return; > + > spin_lock(&stats->lock); > > if (stats->state == new_state)