From patchwork Sun Feb 20 09:04:03 2022 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: 545033 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64CA5C433EF for ; Sun, 20 Feb 2022 09:11:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243460AbiBTJLZ (ORCPT ); Sun, 20 Feb 2022 04:11:25 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:57306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243443AbiBTJLY (ORCPT ); Sun, 20 Feb 2022 04:11:24 -0500 X-Greylist: delayed 398 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sun, 20 Feb 2022 01:11:02 PST Received: from mx-out.tlen.pl (mx-out.tlen.pl [193.222.135.145]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8B9626565 for ; Sun, 20 Feb 2022 01:11:02 -0800 (PST) Received: (wp-smtpd smtp.tlen.pl 23161 invoked from network); 20 Feb 2022 10:04:19 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=o2.pl; s=1024a; t=1645347860; bh=X+qXjhMw4ablrWBQcUFh/9RQ37lVwgA+fXmJmWBXEBs=; h=From:To:Cc:Subject; b=OwmhmOB65Z+svcWXNDTfJdHDSZSVc59X6f/5Yyh8Qp+bWY/F2Lh3yIc4UtUx79ijc FGXlT4h59kNjAW3JJjSXxmQBnv8NNdpq6TZd4xYfAvWx3fBgPetcZun75ArDN01R/n Dlz1LV+uEYpHI+NMFBXKzL2uInDwZ6M8IHjn3qSU= Received: from aaew227.neoplus.adsl.tpnet.pl (HELO localhost.localdomain) (mat.jonczyk@o2.pl@[83.4.126.227]) (envelope-sender ) by smtp.tlen.pl (WP-SMTPD) with SMTP for ; 20 Feb 2022 10:04:19 +0100 From: =?utf-8?q?Mateusz_Jo=C5=84czyk?= To: linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: =?utf-8?q?Mateusz_Jo=C5=84czyk?= , Alessandro Zummo , Alexandre Belloni , Thomas Gleixner , stable@vger.kernel.org Subject: [PATCH] rtc-mc146818-lib: fix locking in mc146818_set_time Date: Sun, 20 Feb 2022 10:04:03 +0100 Message-Id: <20220220090403.153928-1-mat.jonczyk@o2.pl> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-WP-MailID: e253a7ce734dbc8d685bdec651998b01 X-WP-AV: skaner antywirusowy Poczty o2 X-WP-SPAM: NO 0000000 [QWMU] Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org In mc146818_set_time(), CMOS_READ(RTC_CONTROL) was performed without the rtc_lock taken, which is required for CMOS accesses. Fix this. Nothing in kernel modifies RTC_DM_BINARY, so a separate critical section is allowed here. Fixes: dcf257e92622 ("rtc: mc146818: Reduce spinlock section in mc146818_set_time()") Signed-off-by: Mateusz Jończyk Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: Thomas Gleixner Cc: stable@vger.kernel.org --- drivers/rtc/rtc-mc146818-lib.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) base-commit: 754e0b0e35608ed5206d6a67a791563c631cec07 diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index ae9f131b43c0..562f99b664a2 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -232,8 +232,10 @@ int mc146818_set_time(struct rtc_time *time) if (yrs >= 100) yrs -= 100; - if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) - || RTC_ALWAYS_BCD) { + spin_lock_irqsave(&rtc_lock, flags); + save_control = CMOS_READ(RTC_CONTROL); + spin_unlock_irqrestore(&rtc_lock, flags); + if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { sec = bin2bcd(sec); min = bin2bcd(min); hrs = bin2bcd(hrs);