From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 208E332AACB for ; Thu, 9 Jul 2026 14:10:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783606223; cv=none; b=BjQ/S4dL4nIIVDJtrqoSg5aaTJNFKtO6e+2ehFjN41nO+yzaPPXiYuucJt56sgUPJIj/dn660amKChUSPRKaAt3hKKutEwFqiNhy8OkAKL/qkL/3wjlf6DmsxCe0x7lWG4nOJl7DfIqlJOlC+mJ1Ernq4gnXtYtqG05IzG+EZDA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783606223; c=relaxed/simple; bh=4BLLsU9vOS7rCp8dLMHlSOkwuZU0wAhLuE+3sLpyNQo=; h=Message-ID:Date:MIME-Version:Subject:To:From:In-Reply-To: Content-Type:References; b=orBW2icPuTeak19Kber0BOzJLyleb+aZC7nBO1OS+EpWcIXiqcGSHI3p5ZxmPUp4QYD6spwX51V0LButQpOw4TjRNprzXYeUxOpLt/D2d7UkfyIBUSCsov1FWEtec0ULKsLjztfgTnCMJwIwJqvgZUv1zGjd2K+ZyIP5crqYiLE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=hx9Hs79u; arc=none smtp.client-ip=210.118.77.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="hx9Hs79u" Received: from eucas1p1.samsung.com (unknown [182.198.249.206]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20260709141019euoutp019a3105d1712cf3e7b8ea6a6939025114~ApGgQJZhq3160831608euoutp013 for ; Thu, 9 Jul 2026 14:10:19 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20260709141019euoutp019a3105d1712cf3e7b8ea6a6939025114~ApGgQJZhq3160831608euoutp013 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1783606219; bh=vxn7JcGSuRlzoIYoNtpW4xVGFKAj6elywpQGzxj7jKo=; h=Date:Subject:To:From:In-Reply-To:References:From; b=hx9Hs79ug4iLOSi4oGr0425RTpJeHznxcHUJ0U3n5syf9KWbqIkw9XJNArXVLTnlS MUn0xx4CQSdnKESm1X81D2+bW8uIE+nhDkSD33fNQNCLoU0l7x5R72nLtEuzRsqnCt RpvEOFE4BoAQk/Ch//0WJFxk8HiBCzEr8QAPC3g4= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20260709141018eucas1p27e17425eb86087ec8803ada021b8009d~ApGfkIUEs1715017150eucas1p2y; Thu, 9 Jul 2026 14:10:18 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20260709141017eusmtip26d850d8c6797f1decf783eb5313bf180~ApGeUBOfx1597815978eusmtip2h; Thu, 9 Jul 2026 14:10:17 +0000 (GMT) Message-ID: <78e84f2d-0feb-43e0-9d76-9e42f20d1503@samsung.com> Date: Thu, 9 Jul 2026 16:10:16 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Windows) Subject: Re: [PATCH v7 3/7] timekeeping: Account for clocksource tick quantisation via NTP To: Arnd Bergmann , David Woodhouse , Richard Cochran , Wen Gu , Andrew Lunn , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , John Stultz , Thomas Gleixner , Stephen Boyd , Anna-Maria Gleixner , Frederic Weisbecker , shuah , Peter Zijlstra , =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= , Miroslav Lichvar , Julien Ridoux , Ryan Luu , linux-kernel@vger.kernel.org Content-Language: en-US From: Marek Szyprowski In-Reply-To: <6458dfda-f477-4943-896b-857fae5ac871@app.fastmail.com> Content-Transfer-Encoding: 8bit X-CMS-MailID: 20260709141018eucas1p27e17425eb86087ec8803ada021b8009d X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20260709125630eucas1p2d1acb4893a1c72dfba5312453c0971f2 X-EPHeader: CA X-CMS-RootMailID: 20260709125630eucas1p2d1acb4893a1c72dfba5312453c0971f2 References: <20260621220051.1030462-1-dwmw2@infradead.org> <20260621220051.1030462-4-dwmw2@infradead.org> <6458dfda-f477-4943-896b-857fae5ac871@app.fastmail.com> On 09.07.2026 15:19, Arnd Bergmann wrote: > On Thu, Jul 9, 2026, at 14:56, Marek Szyprowski wrote: >> On 21.06.2026 23:53, David Woodhouse wrote: >> >> This patch landed yesterday in linux-next as commit e8bf3955dc2f >> ("timekeeping: Account for clocksource tick quantisation via NTP"). >> In my tests I found that it breaks booting Raspberry Pi 3B and Pi 4B >> boards in ARM 32bit mode with quite old (Debian 10) userspace. > Are you running a 32-bit or 64-bit kernel with your 32-bit userspace? 32bit kernel and 32bit userspace. >> Booting >> freezes just before getting a getty login prompt and no more kernel >> or userspace messages are observed. If I start with init=/bin/bash in >> kernel cmdline and then wait a while and do "exec /sbin/init" I get >> the following additional kernel message: >> >> [  186.867605] Adjusting arch_sys_counter more than 11% (12136 vs 344864995) >> >> then booting freezes again before getting getty prompt. >> >> I can do some more tests, just let me know what will help debugging this >> issue. Other ARM 32bit machines I have work fine with this patch. >> >> Reverting subject together with its dependencies on top of linux-next  >> fixes the issue. > IIRC, there are some variants of these machines with broken > arch timer. Can you check on the working kernel whether > the vdso clock_gettime64 helper is enabled, and whether the > "arm,cpu-registers-not-fw-configured" property is set on > the arm,armv7-timer node? It is not set. I use vanilla dtb from mainline. > If it's not that, the difference between the working and > non-working systems could be the clock frequency behind > the arch timer, which differs wildly between systems, > you should see a "cp15 timer running at ... MHz" message > that tells you what is is I use multi_v7_defconfig from arch/arm, it has CONFIG_VDSO=y. Relevant lines from kernel log (RPi4 board, $subject patch reverted): [    0.000000] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [    0.000001] sched_clock: 32 bits at 1000kHz, resolution 1000ns, wraps every 2147483647500ns [    0.008453] clocksource: timer: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275 ns [    0.017911] bcm2835: system timer (irq = 25) [    0.025858] arch_timer: cp15 timer running at 54.00MHz (sec-phys). [    0.032113] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0xc743ce346, max_idle_ns: 440795203123 ns [    0.043023] sched_clock: 56 bits at 54MHz, resolution 18ns, wraps every 4398046511102ns [    0.051121] Switching to timer-based delay loop, resolution 18ns root@target:~# grep -a "" /sys/firmware/devicetree/base/timer/compatible arm,armv8-timer root@target:~# ls -la /sys/firmware/devicetree/base/timer/ total 0 drwxr-xr-x  2 root root  0 Jan  1 00:00 . drwxr-xr-x 27 root root  0 Jan  1 00:00 .. -r--r--r--  1 root root 16 Jan  1 00:00 compatible -r--r--r--  1 root root 48 Jan  1 00:00 interrupts -r--r--r--  1 root root  6 Jan  1 00:00 name With CONFIG_VDSO disabled same issue happens. Adding "arm,cpu-registers-not-fw-configured" property to arch_timer doesn't change anything. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland