From patchwork Mon Aug 30 17:25:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Mateusz_Jo=C5=84czyk?= X-Patchwork-Id: 1522289 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-rtc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=o2.pl header.i=@o2.pl header.a=rsa-sha256 header.s=1024a header.b=vpFJMJQy; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4Gyy0Q0CyHz9sVw for ; Tue, 31 Aug 2021 03:26:14 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234565AbhH3R1F (ORCPT ); Mon, 30 Aug 2021 13:27:05 -0400 Received: from mx-out.tlen.pl ([193.222.135.175]:41279 "EHLO mx-out.tlen.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232969AbhH3R1F (ORCPT ); Mon, 30 Aug 2021 13:27:05 -0400 Received: (wp-smtpd smtp.tlen.pl 21362 invoked from network); 30 Aug 2021 19:26:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=o2.pl; s=1024a; t=1630344369; bh=4X/yZ1ojBs7hoJvotzd+ipQiT/uhdl8K5BGgHHVn90E=; h=From:To:Cc:Subject; b=vpFJMJQytJC6AAnQFOZxfTw4Z8OvHPd3oKpfCGSlEvwHaTe6mxHn4lqL7hlxxg4w7 J3dknOhukyb7JKqh8/ruZqNbT83N4C6aA68L0SfyAUaPUXo7rYfftEMnCq0qAgap1S rZdPuOe0s9Vy7ODGBdDX+XpNYLrUFOuXgVTrbeeM= Received: from ablt14.neoplus.adsl.tpnet.pl (HELO localhost.localdomain) (mat.jonczyk@o2.pl@[83.7.213.14]) (envelope-sender ) by smtp.tlen.pl (WP-SMTPD) with SMTP for ; 30 Aug 2021 19:26:08 +0200 From: =?utf-8?q?Mateusz_Jo=C5=84czyk?= To: linux-rtc@vger.kernel.org Cc: =?utf-8?q?Mateusz_Jo=C5=84czyk?= , Alessandro Zummo , Alexandre Belloni , stable@vger.kernel.org Subject: [PATCH] rtc-cmos: take rtc_lock while accessing CMOS Date: Mon, 30 Aug 2021 19:25:41 +0200 Message-Id: <20210830172541.62588-1-mat.jonczyk@o2.pl> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-WP-MailID: ac92081073b4ea01d3161b4d615bbfe1 X-WP-AV: skaner antywirusowy Poczty o2 X-WP-SPAM: NO 0000000 [QfMk] Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org Reading from the CMOS involves writing to the index register and then reading from the data register. Therefore access to the CMOS has to be serialized with a spinlock. An invocation in cmos_set_alarm was not serialized with rtc_lock, fix this. Use spin_lock_irq() like the rest of the function. Nothing in kernel modifies the RTC_DM_BINARY bit, so use a separate pair of spin_lock_irq() / spin_unlock_irq() before doing the math. Signed-off-by: Mateusz Jończyk Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: stable@vger.kernel.org Reviewed-by: Nobuhiro Iwamatsu --- drivers/rtc/rtc-cmos.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index 0fa66d1039b9..e6ff0fb7591b 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -463,7 +463,10 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) min = t->time.tm_min; sec = t->time.tm_sec; + spin_lock_irq(&rtc_lock); rtc_control = CMOS_READ(RTC_CONTROL); + spin_unlock_irq(&rtc_lock); + if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { /* Writing 0xff means "don't care" or "match all". */ mon = (mon <= 12) ? bin2bcd(mon) : 0xff;