From patchwork Fri Dec 4 19:09:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manaf Meethalavalappu Pallikunhi X-Patchwork-Id: 11952171 X-Patchwork-Delegate: rui.zhang@intel.com 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=-16.8 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,USER_AGENT_GIT 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 CDB90C4361A for ; Fri, 4 Dec 2020 19:11:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75C0522C9F for ; Fri, 4 Dec 2020 19:11:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729779AbgLDTLE (ORCPT ); Fri, 4 Dec 2020 14:11:04 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:31403 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726392AbgLDTLE (ORCPT ); Fri, 4 Dec 2020 14:11:04 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1607109046; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=UMsjcuAWdu22fCFAdUNp3aiqXyrJYaP8lEGrfsmhYng=; b=qIichflKZHu2IC0NGTjUoj0/GrdgmDEsyXXE7kdRQpegHOyiUgH5TFvCSycYzy161O/6VzVq MgO2cR5Bq5wwINFkoa1hqx8p0Mpx6OzGAfLrZUUgT3ZFlArNsxz72Tfk5PXQXQx0v9IYNnkB JvrkfSH9LvoJRxWR5dcWXehcCPc= X-Mailgun-Sending-Ip: 69.72.43.15 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-n08.prod.us-east-1.postgun.com with SMTP id 5fca898f9c3ccbec63b561bc (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 04 Dec 2020 19:10:07 GMT Sender: manafm=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 0EEB9C43463; Fri, 4 Dec 2020 19:10:07 +0000 (UTC) Received: from codeaurora.org (unknown [202.46.22.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: manafm) by smtp.codeaurora.org (Postfix) with ESMTPSA id 96357C433CA; Fri, 4 Dec 2020 19:10:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 96357C433CA Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=manafm@codeaurora.org From: Manaf Meethalavalappu Pallikunhi To: Zhang Rui , Eduardo Valentin , Daniel Lezcano , Amit Kucheria , Ram Chandrasekar Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Manaf Meethalavalappu Pallikunhi Subject: [PATCH] drivers: thermal: Add NULL pointer check before using cooling device stats Date: Sat, 5 Dec 2020 00:39:51 +0530 Message-Id: <1607108991-31948-1-git-send-email-manafm@codeaurora.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org 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 or cooling stats sysfs will 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 | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 473449b..a5e4855 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) @@ -848,6 +851,9 @@ static ssize_t total_trans_show(struct device *dev, struct cooling_dev_stats *stats = cdev->stats; int ret; + if (!stats) + return -ENODEV; + spin_lock(&stats->lock); ret = sprintf(buf, "%u\n", stats->total_trans); spin_unlock(&stats->lock); @@ -864,6 +870,9 @@ time_in_state_ms_show(struct device *dev, struct device_attribute *attr, ssize_t len = 0; int i; + if (!stats) + return -ENODEV; + spin_lock(&stats->lock); update_time_in_state(stats); @@ -882,8 +891,12 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf, { struct thermal_cooling_device *cdev = to_cooling_device(dev); struct cooling_dev_stats *stats = cdev->stats; - int i, states = stats->max_states; + int i, states; + + if (!stats) + return -ENODEV; + states = stats->max_states; spin_lock(&stats->lock); stats->total_trans = 0; @@ -907,6 +920,9 @@ static ssize_t trans_table_show(struct device *dev, ssize_t len = 0; int i, j; + if (!stats) + return -ENODEV; + len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n"); len += snprintf(buf + len, PAGE_SIZE - len, " : "); for (i = 0; i < stats->max_states; i++) {