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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 C79D5C4741F for ; Tue, 29 Sep 2020 11:04:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 675DF20C09 for ; Tue, 29 Sep 2020 11:04:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601377496; bh=ktwXjJcoQBFeqzF3sVgSfhk9Th+iEadBnBf1ZaBJVBA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WHtGN2AQNjhE6ivxpL+CcbxsSwem0s7xzENZzBfnqdU0VZyl/MdDaqYBGTlys9Ld7 WpxDToQdw8/91yFvmUn8zsL7GXVS/DW/y1r3p200Qobzb/7z8yQM4U1iMCKsASqQ4Y 89uDJgO6vzM214VzSBaVYYjtUvUSBWgA5kTqeypc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728670AbgI2LEz (ORCPT ); Tue, 29 Sep 2020 07:04:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:41058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728663AbgI2LEs (ORCPT ); Tue, 29 Sep 2020 07:04:48 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 EA47E21734; Tue, 29 Sep 2020 11:04:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601377488; bh=ktwXjJcoQBFeqzF3sVgSfhk9Th+iEadBnBf1ZaBJVBA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ruPFbt242Rf3weFnVuZUI/MdwZtGRP2J5xSnQ13d2TPK0nGCG1DfIJgdFq2Baiavn 8zL6CUNw/A4sbwTr3E6RYgUSFp/ZQwlMHjyl5zZ7yXBHzF3MiS9R05i0SovBBv8Q4B xoRkw23ZNjkJ95+C+LZteaDW/Cstko0IGiApONdI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Madhuparna Bhowmik , Sasha Levin Subject: [PATCH 4.4 53/85] drivers: char: tlclk.c: Avoid data race between init and interrupt handler Date: Tue, 29 Sep 2020 13:00:20 +0200 Message-Id: <20200929105930.882323256@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105928.198942536@linuxfoundation.org> References: <20200929105928.198942536@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Madhuparna Bhowmik [ Upstream commit 44b8fb6eaa7c3fb770bf1e37619cdb3902cca1fc ] After registering character device the file operation callbacks can be called. The open callback registers interrupt handler. Therefore interrupt handler can execute in parallel with rest of the init function. To avoid such data race initialize telclk_interrupt variable and struct alarm_events before registering character device. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Madhuparna Bhowmik Link: https://lore.kernel.org/r/20200417153451.1551-1-madhuparnabhowmik10@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/char/tlclk.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/char/tlclk.c b/drivers/char/tlclk.c index 100cd1de9939d..59e1e94d12c01 100644 --- a/drivers/char/tlclk.c +++ b/drivers/char/tlclk.c @@ -777,17 +777,21 @@ static int __init tlclk_init(void) { int ret; + telclk_interrupt = (inb(TLCLK_REG7) & 0x0f); + + alarm_events = kzalloc( sizeof(struct tlclk_alarms), GFP_KERNEL); + if (!alarm_events) { + ret = -ENOMEM; + goto out1; + } + ret = register_chrdev(tlclk_major, "telco_clock", &tlclk_fops); if (ret < 0) { printk(KERN_ERR "tlclk: can't get major %d.\n", tlclk_major); + kfree(alarm_events); return ret; } tlclk_major = ret; - alarm_events = kzalloc( sizeof(struct tlclk_alarms), GFP_KERNEL); - if (!alarm_events) { - ret = -ENOMEM; - goto out1; - } /* Read telecom clock IRQ number (Set by BIOS) */ if (!request_region(TLCLK_BASE, 8, "telco_clock")) { @@ -796,7 +800,6 @@ static int __init tlclk_init(void) ret = -EBUSY; goto out2; } - telclk_interrupt = (inb(TLCLK_REG7) & 0x0f); if (0x0F == telclk_interrupt ) { /* not MCPBL0010 ? */ printk(KERN_ERR "telclk_interrupt = 0x%x non-mcpbl0010 hw.\n", @@ -837,8 +840,8 @@ out3: release_region(TLCLK_BASE, 8); out2: kfree(alarm_events); -out1: unregister_chrdev(tlclk_major, "telco_clock"); +out1: return ret; } -- 2.25.1