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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 DF690C43381 for ; Mon, 1 Feb 2021 14:00:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B766364E97 for ; Mon, 1 Feb 2021 14:00:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232502AbhBAOAC (ORCPT ); Mon, 1 Feb 2021 09:00:02 -0500 Received: from depni-mx.sinp.msu.ru ([213.131.7.21]:25 "EHLO depni-mx.sinp.msu.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232031AbhBAN76 (ORCPT ); Mon, 1 Feb 2021 08:59:58 -0500 X-Greylist: delayed 351 seconds by postgrey-1.27 at vger.kernel.org; Mon, 01 Feb 2021 08:59:55 EST Received: from spider (unknown [176.192.246.239]) by depni-mx.sinp.msu.ru (Postfix) with ESMTPSA id 59A8C1BF45C; Mon, 1 Feb 2021 16:53:53 +0300 (MSK) From: Serge Belyshev To: Thomas Gleixner Cc: Dirk Gouders , =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= , LKML , Alexandre Belloni , Jason Gunthorpe , Miroslav Lichvar , John Stultz , Prarit Bhargava , Alessandro Zummo , linux-rtc@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH V2] rtc: mc146818: Detect and handle broken RTCs References: <20201206214613.444124194@linutronix.de> <20201206220541.594826678@linutronix.de> <19a7753c-c492-42e4-241a-8a052b32bb63@digikod.net> <871re7hlsg.fsf@nanos.tec.linutronix.de> <98cb59e8-ecb4-e29d-0b8f-73683ef2bee7@digikod.net> <87y2gfg18p.fsf@nanos.tec.linutronix.de> <87tur3fx7w.fsf@nanos.tec.linutronix.de> Date: Mon, 01 Feb 2021 16:53:20 +0300 In-Reply-To: (Dirk Gouders's message of "Sun, 31 Jan 2021 11:59:49 +0100") Message-ID: <877dnrc2sv.fsf@depni.sinp.msu.ru> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! "Me too": > --- a/drivers/rtc/rtc-mc146818-lib.c > +++ b/drivers/rtc/rtc-mc146818-lib.c > @@ -21,6 +21,13 @@ unsigned int mc146818_get_time(struct rt > > again: > spin_lock_irqsave(&rtc_lock, flags); > + /* Ensure that the RTC is accessible. Bit 0-6 must be 0! */ > + if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x7f) != 0)) { > + spin_unlock_irqrestore(&rtc_lock, flags); > + memset(time, 0xff, sizeof(*time)); > + return 0; > + } > + ... triggers here on a different box (Xiaomi mi notebook air 12.5): [ 3.524002] ------------[ cut here ]------------ [ 3.528317] WARNING: CPU: 3 PID: 273 at drivers/rtc/rtc-mc146818-lib.c:25 mc146818_get_time+0x1b6/0x210 [ 3.532558] CPU: 3 PID: 273 Comm: udevadm Not tainted 5.11.0-rc6 #760 [ 3.536748] Hardware name: Timi TM1612/TM1612, BIOS A04 08/06/2016 [ 3.540947] RIP: 0010:mc146818_get_time+0x1b6/0x210 [ 3.545103] Code: 76 0b 0f b6 d0 83 ea 13 6b d2 64 01 d5 83 fd 45 89 6b 14 7f 06 83 c5 64 89 6b 14 41 83 ed 01 b8 02 00 00 00 44 89 6b 10 eb 39 <0f> 0b 48 c7 c7 b4 e0 9e 82 48 89 ee e8 29 6b 34 00 48 c7 03 ff ff [ 3.549883] RSP: 0000:ffffc900012efe30 EFLAGS: 00010002 [ 3.554387] RAX: 0000000000000081 RBX: ffffc900012efe64 RCX: 000000000005b8d7 [ 3.558867] RDX: 0000000000000001 RSI: ffff8881000aa000 RDI: 000000000000000d [ 3.563333] RBP: 0000000000000046 R08: 0000000000000004 R09: fffffffe5e075ac6 [ 3.567748] iwlwifi 0000:02:00.0: Applying debug destination EXTERNAL_DRAM [ 3.567822] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 3.567827] R13: ffffc900012efedc R14: 0000000000000008 R15: ffff888100051200 [ 3.577223] FS: 0000000000000000(0000) GS:ffff88816ad80000(0000) knlGS:0000000000000000 [ 3.579870] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3.581947] CR2: 00007fface455e28 CR3: 0000000103244005 CR4: 00000000003706a0 [ 3.583836] Call Trace: [ 3.585699] hpet_rtc_interrupt+0x1af/0x220 [ 3.587585] __handle_irq_event_percpu+0x5a/0xc0 [ 3.589230] handle_irq_event_percpu+0x1b/0x50 [ 3.590673] handle_irq_event+0x22/0x40 [ 3.592107] handle_edge_irq+0x6b/0x190 [ 3.593545] common_interrupt+0x67/0x130 [ 3.594983] ? asm_common_interrupt+0x8/0x40 [ 3.596432] asm_common_interrupt+0x1e/0x40 [ 3.597618] RIP: 0033:0x7ffaceac9b31 [ 3.598794] Code: 48 83 fe 0a 0f 87 f5 fe ff ff be 41 ff ff 6f 48 29 d6 48 89 04 f1 e9 e4 fe ff ff 48 85 ff 74 79 49 8b 44 24 60 48 85 c0 74 04 <48> 01 78 08 49 8b 44 24 58 48 85 c0 74 04 48 01 78 08 49 8b 44 24 [ 3.600048] RSP: 002b:00007ffc12303b00 EFLAGS: 00010202 [ 3.601343] RAX: 00007fface455e20 RBX: 000000006ffffdff RCX: 00007fface80c040 [ 3.602587] RDX: 0000000000000000 RSI: 0000000000000029 RDI: 00007fface451000 [ 3.603809] RBP: 00007ffc12303c50 R08: 000000006fffffff R09: 00000000effffef5 [ 3.605015] R10: 0000000070000022 R11: 0000000000000032 R12: 00007fface80c000 [ 3.606223] R13: 000000006ffffeff R14: 000000006ffffe35 R15: 00007ffc12303ce0 [ 3.607421] ---[ end trace 5922ddf43b0f7b83 ]--- [ 3.608692] hpet: Lost 3 RTC interrupts