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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AE04C433FE for ; Thu, 21 Oct 2021 18:29:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41CBF60F22 for ; Thu, 21 Oct 2021 18:29:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231502AbhJUSbj (ORCPT ); Thu, 21 Oct 2021 14:31:39 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:65451 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230020AbhJUSbh (ORCPT ); Thu, 21 Oct 2021 14:31:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1634840962; x=1666376962; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=SQAoZ11ZnWSeNhTwVlHh0SqRjU4gwrk7g08gzFYTsdA=; b=VKVDcVIHwc7DFzb1dxZef/E6A67Jk1WxXRs5imNwsULNQVPB5dzeIIZb bFmrJ0FD4RiPrXHSrU0oJWFbkNMSy5buVoiIziqBmGwnnj0VjRWSSi+Bl NFQwm2W6M+/bHVBf0Gh18ey7RKRr5YeUIh3dlbwoL0W3RfOzz4CvFiPHv Y=; Received: from ironmsg08-lv.qualcomm.com ([10.47.202.152]) by alexa-out.qualcomm.com with ESMTP; 21 Oct 2021 11:29:21 -0700 X-QCInternal: smtphost Received: from nalasex01a.na.qualcomm.com ([10.47.209.196]) by ironmsg08-lv.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Oct 2021 11:29:20 -0700 Received: from [10.47.233.232] (10.49.16.6) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.922.7; Thu, 21 Oct 2021 11:29:20 -0700 Subject: Re: [PATCH v2] thermal: Fix a NULL pointer dereference To: Daniel Lezcano , Zhang Rui , Amit Kucheria CC: , , David Collins , Manaf Meethalavalappu Pallikunhi , Ram Chandrasekar , References: <1631041289-11804-1-git-send-email-quic_subbaram@quicinc.com> <003252f2-510f-e9ea-0032-6034f26aad11@linaro.org> <16af9946-b662-0bbf-206f-278b7ef98123@quicinc.com> <8cda69a6-907b-e09e-ba64-011b0216a4df@quicinc.com> From: Subbaraman Narayanamurthy Message-ID: <1e0371e7-5c15-a552-870a-a501ec11a8f9@quicinc.com> Date: Thu, 21 Oct 2021 11:29:20 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [10.49.16.6] X-ClientProxiedBy: nalasex01b.na.qualcomm.com (10.47.209.197) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/19/21 12:35 AM, Daniel Lezcano wrote: > On 19/10/2021 03:21, Subbaraman Narayanamurthy wrote: >> On 10/8/21 12:50 PM, Subbaraman Narayanamurthy wrote: >>> On 10/6/21 4:08 AM, Daniel Lezcano wrote: > [ ... ] > >>> /sys/devices/virtual/thermal/thermal_zone87 # echo 120000 > trip_point_0_temp   >>> [  184.290964][  T211] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 >>> [  184.300896][  T211] Mem abort info:                                          >>> [  184.304486][  T211]   ESR = 0x96000006                                       >>> [  184.308348][  T211]   EC = 0x25: DABT (current EL), IL = 32 bits             >>> [  184.314531][  T211]   SET = 0, FnV = 0                                       >>> [  184.318384][  T211]   EA = 0, S1PTW = 0                                      >>> [  184.322323][  T211] Data abort info:                                         >>> [  184.325993][  T211]   ISV = 0, ISS = 0x00000006                              >>> [  184.330655][  T211]   CM = 0, WnR = 0                                        >>> [  184.334425][  T211] user pgtable: 4k pages, 39-bit VAs, pgdp=000000081a7a2000 >>> [  184.341750][  T211] [0000000000000020] pgd=000000081a7a7003, p4d=000000081a7a7003, pud=000000081a7a7003, pmd=0000000000000000 >>> [  184.353359][  T211] Internal error: Oops: 96000006 [#1] PREEMPT SMP          >>> [  184.359797][  T211] Dumping ftrace buffer:                                   >>> [  184.364001][  T211]    (ftrace buffer empty) >>> >>> Hope this helps. >> Hi Daniel, >> Have you got a chance to look at this? > Hi Subbaraman, > > Actually, I think the root problem is the thermal zone is showing up > while there is no sensor associated with it. You can read the > temperature and get a kernel warning also. > > That's what should be fixed IMO. > Hi Daniel, If I understand your statement correctly, are you saying that a thermal_zone device should be created only after a thermal sensor driver supplying it probes? >From what I can see, thermal_init()     --> of_parse_thermal_zones()             --> thermal_zone_device_register()                     --> thermal_zone_create_device_groups()                                                     device_register() with thermal_zone%d This happens way before a thermal sensor driver probes. So, creating a thermal_zone device only after its thermal sensor probes would require more changes to the framework. Also, I see a similar NULL check exists in the framework code already. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/thermal/thermal_of.c?h=v5.15-rc6#n103 So, extending the logic for other callsites (below) makes sense to me. - of_thermal_get_temp() - of_thermal_set_emul_temp() - of_thermal_get_trend() - of_thermal_set_trip_temp() Thanks, Subbaraman