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 ED152C4727C for ; Tue, 29 Sep 2020 11:33:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C207A23B44 for ; Tue, 29 Sep 2020 11:33:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379239; bh=2UQ9DFaxS2qeBIdJST9eYG/tl8Ou/LtUg3wFI3kjC04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZNdmGpl/qr9lESoQ8d6pwFFk7jQcFGitcnxZAtszAODP8jnsbVCFF5uDGfMxoHWr+ DtfqtDRwmWYZp/fMSMAga0Up9rq1dLU8kyVsXQ9eqpWUwkzI2r4bUeJJ48OzInIcAP 0bdZhSIDnu5aFwUdomd/PjlxSeRiaCtXU4s3MA8s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729702AbgI2Ld5 (ORCPT ); Tue, 29 Sep 2020 07:33:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:50012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729604AbgI2Ld1 (ORCPT ); Tue, 29 Sep 2020 07:33:27 -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 B4B3223B99; Tue, 29 Sep 2020 11:26:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378812; bh=2UQ9DFaxS2qeBIdJST9eYG/tl8Ou/LtUg3wFI3kjC04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p4KGSPV4V0briqR1i9iF0gZjkvc45jHtiB7/iPdL7sGIjxi+R1JdvzLgR7jq++vH4 ooR25f/ykC1XtIZ5N3wjSN8diOYp5sGD7d1nVWFHI1nbDOLsV5FLyM4eFrtA6Wegy1 +hq/KAt67TnIktHa+fhdL2jhB7m5d9n4wRSnZgys= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Madhuparna Bhowmik , Sasha Levin Subject: [PATCH 4.19 148/245] drivers: char: tlclk.c: Avoid data race between init and interrupt handler Date: Tue, 29 Sep 2020 12:59:59 +0200 Message-Id: <20200929105954.189934904@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105946.978650816@linuxfoundation.org> References: <20200929105946.978650816@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 8eeb4190207d1..dce22b7fc5449 100644 --- a/drivers/char/tlclk.c +++ b/drivers/char/tlclk.c @@ -776,17 +776,21 @@ 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")) { @@ -795,7 +799,6 @@ 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", @@ -836,8 +839,8 @@ out3: release_region(TLCLK_BASE, 8); out2: kfree(alarm_events); -out1: unregister_chrdev(tlclk_major, "telco_clock"); +out1: return ret; } -- 2.25.1