From patchwork Tue Sep 29 11:00:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 290770 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 852F1C4741F for ; Tue, 29 Sep 2020 12:38:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35BC92076A for ; Tue, 29 Sep 2020 12:38:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601383139; bh=LTl5jy1HfdZaViFwcvCdmYJVjKxaG0vJezeAgYPRQpU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=axNZgGwmBv/pAcsfY/XGEKb+fetNgXbRA5revhEcy9MW7jA0NEwOmJeHFYDNhSw+o rjbi7zjtEn37imNW+y9n7Li8mXuiZYgZU46hd7apVvubIoqNcvrmnHRxpXtfGvbO0o u9IFgO4DMNA1Zf5SMWSZWYYHjGao8TSbU5Oygc+Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729629AbgI2LRJ (ORCPT ); Tue, 29 Sep 2020 07:17:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:33998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729624AbgI2LRI (ORCPT ); Tue, 29 Sep 2020 07:17:08 -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 0446921D7D; Tue, 29 Sep 2020 11:17:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378228; bh=LTl5jy1HfdZaViFwcvCdmYJVjKxaG0vJezeAgYPRQpU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I/LaOguonNnBPwy9uqlAcykDpQoqBTRP0e4AQJxL4CpF1yXkweWqJZzfgpNFco1x1 kSr+1VXZVOoCPYAC+w0judxLe/HNnows7Ip8zSN1KDT2kbSpHO5PF0DetR8z28c3oV HMO3yviDDKJSPA/xKGfyyiTfQXsYrsVZa/0gTKWg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Madhuparna Bhowmik , Sasha Levin Subject: [PATCH 4.14 106/166] drivers: char: tlclk.c: Avoid data race between init and interrupt handler Date: Tue, 29 Sep 2020 13:00:18 +0200 Message-Id: <20200929105940.499721714@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105935.184737111@linuxfoundation.org> References: <20200929105935.184737111@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 6210bff46341e..52fadc46e7a97 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; }