[{"id":3674227,"web_url":"http://patchwork.ozlabs.org/comment/3674227/","msgid":"<87wlyi4yrj.ffs@tglx>","list_archive_url":null,"date":"2026-04-07T14:43:12","subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","submitter":{"id":92397,"url":"http://patchwork.ozlabs.org/api/people/92397/","name":"Thomas Gleixner","email":"tglx@kernel.org"},"content":"On Tue, Apr 07 2026 at 10:54, Thomas Gleixner wrote:\n> There needs to be some discussion about the scope of backporting. The first\n> patch preventing the stall is obviously a backport candidate. The remaining\n> series can be obviously argued about, but in my opinion it should be\n> backported as well as it prevents stupid or malicious user space from\n> generating tons of pointless timer interrupts.\n\nPeter and me just discussed it over IRC. With the clockevents prevention\nin place, the effect of stupid/malicious code is pretty much affecting\nonly the user space task itself. As the timer is forced to expire once\nthe clockevent device has been force armed, it won't have other side\neffects as device interrupts or IPIs are not blocked out and in the\nworst case marginally delayed by the high frequency timer interrupt.\n\nOnce the task is scheduled out that subsides as there is nothing which\nre-arms the timer anymore.\n\nSo we should be fine with backporting the clockevents fix and leave the\nother parts of the series for upstream only. I still need to investigate\nhow all of that affects the pending changes vs. TSC deadline timer (and\nsimilar devices) which are not going to reach that modified clockevents\ncode anymore.\n\nThanks,\n\n tglx","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=cgEZXQhl;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11691-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"cgEZXQhl\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fqpxv0v30z1xy1\n\tfor ; Wed, 08 Apr 2026 00:49:39 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby tor.lore.kernel.org (Postfix) with ESMTP id 0265F30711AA\n\tfor ; Tue, 7 Apr 2026 14:43:23 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 4633327B35F;\n\tTue, 7 Apr 2026 14:43:17 +0000 (UTC)","from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id C41B41A9FB0;\n\tTue, 7 Apr 2026 14:43:16 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id B59A2C116C6;\n\tTue, 7 Apr 2026 14:43:15 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775572996; cv=none;\n b=k3RNVqHlODmTWBuQLxpAD4oMSiHadDqFlvR+ENGVNhRfmYRCrOgC3hTjcrpqXa1rOnKQ8W9RmgDedu5G+VIkkieLMP7C+vWLKz8nYWl2YW49hIxfsMy2RP8zZLds9o06ATTl0445/RaB05FbnkNojNJKeHMCU5lNYdDBNwXdF8c=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775572996; c=relaxed/simple;\n\tbh=x0V8HDMD/+ttteoDJUS2U88l+YhpYc2Fl6aWUWMCqok=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID:\n\t MIME-Version:Content-Type;\n b=QTr7FUADV7sZqWfL/0/TcCvRtFxqNwmdl/yUHgjuytKLAiGC1gUCsbxGjMfjgdz7gMVsiN5dJt5FHOmL9My4beE4fKr5s2PN2tiO1TEIiCc26JC056b24GhtvltCmGusCrzn1bQJS9BWBGyyoMXH/q7vUTm8eyGIbCsYhLsekkc=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=cgEZXQhl; arc=none smtp.client-ip=10.30.226.201","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1775572996;\n\tbh=x0V8HDMD/+ttteoDJUS2U88l+YhpYc2Fl6aWUWMCqok=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:From;\n\tb=cgEZXQhlUkaZWRnOU01DIi6XvkoZTXLmpvxfJEv5ObbEvAfkis42+82Rx1GtRblUH\n\t 52I4eR2pw8DzuAAkIsYojEYtExUnKEiGccUTWBmxBxYmx5sqLp+cJ2PDbRkeEiS3T6\n\t h4D+yrB994XCj2OtlWoL/u+lW34T1uYoLC4ipDC/aOFbRTdmT6OTKpHiaqtecX/fLD\n\t uF7FZ6g3UIyXQNi234QAAH6tSrtqxYPWzedwnfBsa48ORmOB4Xr1Fd+nbELRak58w3\n\t WPpsp5a4TKpGpL5TEumDy+EKbQY1vkazGFN11WFGsPMsMYQ/mCjCmN4MHAd8uUZind\n\t RLvFPmrHC9v9g==","From":"Thomas Gleixner ","To":"LKML ","Cc":"Calvin Owens , Peter Zijlstra ,\n Anna-Maria Behnsen , Frederic Weisbecker\n , Ingo Molnar , John Stultz\n , Stephen Boyd , Alexander Viro\n , Christian Brauner , Jan\n Kara , linux-fsdevel@vger.kernel.org, Sebastian Reichel\n , linux-pm@vger.kernel.org, Pablo Neira Ayuso\n , Florian Westphal , Phil Sutter\n , netfilter-devel@vger.kernel.org, coreteam@netfilter.org","Subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","In-Reply-To":"<20260407083219.478203185@kernel.org>","References":"<20260407083219.478203185@kernel.org>","Date":"Tue, 07 Apr 2026 16:43:12 +0200","Message-ID":"<87wlyi4yrj.ffs@tglx>","Precedence":"bulk","X-Mailing-List":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Type":"text/plain"}},{"id":3674299,"web_url":"http://patchwork.ozlabs.org/comment/3674299/","msgid":"<87qzoq4uef.ffs@tglx>","list_archive_url":null,"date":"2026-04-07T16:17:28","subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","submitter":{"id":92397,"url":"http://patchwork.ozlabs.org/api/people/92397/","name":"Thomas Gleixner","email":"tglx@kernel.org"},"content":"On Tue, Apr 07 2026 at 16:43, Thomas Gleixner wrote:\n> On Tue, Apr 07 2026 at 10:54, Thomas Gleixner wrote:\n>> There needs to be some discussion about the scope of backporting. The first\n>> patch preventing the stall is obviously a backport candidate. The remaining\n>> series can be obviously argued about, but in my opinion it should be\n>> backported as well as it prevents stupid or malicious user space from\n>> generating tons of pointless timer interrupts.\n>\n> Peter and me just discussed it over IRC. With the clockevents prevention\n> in place, the effect of stupid/malicious code is pretty much affecting\n> only the user space task itself. As the timer is forced to expire once\n> the clockevent device has been force armed, it won't have other side\n> effects as device interrupts or IPIs are not blocked out and in the\n> worst case marginally delayed by the high frequency timer interrupt.\n>\n> Once the task is scheduled out that subsides as there is nothing which\n> re-arms the timer anymore.\n>\n> So we should be fine with backporting the clockevents fix and leave the\n> other parts of the series for upstream only. I still need to investigate\n> how all of that affects the pending changes vs. TSC deadline timer (and\n> similar devices) which are not going to reach that modified clockevents\n> code anymore.\n\nIt's pretty much the same as the above with the difference that a timer\narmed in the past will result in an instantaneous interrupt as the\ncoupled event devices must provide a less than or equal comparator. So\nagain the task can only delay itself with hrtimer interrupts.\n\nThanks,\n\n tglx","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=vJC/Xash;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11693-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"vJC/Xash\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fqs4S6yLMz1xtJ\n\tfor ; Wed, 08 Apr 2026 02:25:28 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby tor.lore.kernel.org (Postfix) with ESMTP id E51DA304A8A1\n\tfor ; Tue, 7 Apr 2026 16:17:39 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 6AAB93BAD9B;\n\tTue, 7 Apr 2026 16:17:33 +0000 (UTC)","from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id EA7C233D4F3;\n\tTue, 7 Apr 2026 16:17:32 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id B8507C19424;\n\tTue, 7 Apr 2026 16:17:31 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775578653; cv=none;\n b=Q86eJ/Ds5WnlrVKF0FGe+fXyoEyHNwpJutkNJAReLA3HWcEDwA03A6bcGxErmDp1J0CBncZ27HDgWDi+Fv+E+rO+MxqMFlpjWglM36vH4kbbvypq4xH8lImR16t+u/ZZ1Xt077SQvQnZ/j5FyxPOT+C21z3epHlrHX/3c2/xCiE=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775578653; c=relaxed/simple;\n\tbh=TpzE9QxM02oe3UDWE662FRdcVm7uQTpTmnONiXx9w2E=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID:\n\t MIME-Version:Content-Type;\n b=ZwKpIwuN/7Iyml7SM1HvE07zNcOEWaX0Flzfg7pr1MGRcV0AQXs0LyQiwDx5hMdfRLpCDSLbA0FqMZRUnJGcKYEls2ZwUT5FBLdYqNTdwBTjS8Ch8U9ua1j6D1XSNuMBf4xHY6It2KZweZ0RN2Hw6sp4EtW7RcvL6fFjK1eOuVE=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=vJC/Xash; arc=none smtp.client-ip=10.30.226.201","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1775578652;\n\tbh=TpzE9QxM02oe3UDWE662FRdcVm7uQTpTmnONiXx9w2E=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:From;\n\tb=vJC/XashBFAGUqoMTahwwK2LPXUQhnx8iYN66z8szRJSO90ZEjxgvYxZwZ0a0uvfe\n\t iCdKNeHU6jdsqOWdqZ9YgoI8qD15tLAlhn99Tvw1Ek0owaeYsFUSgAyFfIcy+eW5b7\n\t lscaEdf8esLGHSnsHNi/XO55Td5qXc2kBXUwUwc9oyCdXqcDbmbH5W1/RMJjgEFfFU\n\t foOHPmK6802vjKzvmR/tFxF1RCcnDnAYom+5bJDKgG5JJasAaRIEKLjUcTkA5n/gZ3\n\t zErn01qFYH2wJNwwebtYzD2UTMuhcyEB8xYSQ2L8y5XD8PFSbcMmQtTWTY8//8Gpa2\n\t RvMT8OLyH+J/g==","From":"Thomas Gleixner ","To":"LKML ","Cc":"Calvin Owens , Peter Zijlstra ,\n Anna-Maria Behnsen , Frederic Weisbecker\n , Ingo Molnar , John Stultz\n , Stephen Boyd , Alexander Viro\n , Christian Brauner , Jan\n Kara , linux-fsdevel@vger.kernel.org, Sebastian Reichel\n , linux-pm@vger.kernel.org, Pablo Neira Ayuso\n , Florian Westphal , Phil Sutter\n , netfilter-devel@vger.kernel.org, coreteam@netfilter.org","Subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","In-Reply-To":"<87wlyi4yrj.ffs@tglx>","References":"<20260407083219.478203185@kernel.org> <87wlyi4yrj.ffs@tglx>","Date":"Tue, 07 Apr 2026 18:17:28 +0200","Message-ID":"<87qzoq4uef.ffs@tglx>","Precedence":"bulk","X-Mailing-List":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Type":"text/plain"}},{"id":3674317,"web_url":"http://patchwork.ozlabs.org/comment/3674317/","msgid":"","list_archive_url":null,"date":"2026-04-07T17:38:06","subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","submitter":{"id":91507,"url":"http://patchwork.ozlabs.org/api/people/91507/","name":"Calvin Owens","email":"calvin@wbinvd.org"},"content":"On Tuesday 04/07 at 10:54 +0200, Thomas Gleixner wrote:\n> Calvin reported an odd NMI watchdog lockup which claims that the CPU locked\n> up in user space:\n> \n> https://lore.kernel.org/lkml/acMe-QZUel-bBYUh@mozart.vkv.me/\n> \n> He provided a reproducer, which sets up a timerfd based timer and then\n> rearms it in a loop with an absolute expiry time of 1ns.\n\nThe original AMD machines survive the reproducer with this series.\n\nTested-by: Calvin Owens \n\nI'm happy to test subsets of it and stable backports too, if that's\nhelpful, just let me know.\n\nThanks,\nCalvin\n\n> As the expiry time is in the past, the timer ends up as the first expiring\n> timer in the per CPU hrtimer base and the clockevent device is programmed\n> with the minimum delta value. If the machine is fast enough, this ends up\n> in a endless loop of programming the delta value to the minimum value\n> defined by the clock event device, before the timer interrupt can fire,\n> which starves the interrupt and consequently triggers the lockup detector\n> because the hrtimer callback of the lockup mechanism is never invoked.\n> \n> The first patch in the series changes the clockevent set next event\n> mechanism to prevent reprogramming of the clockevent device when the\n> minimum delta value was programmed unless the new delta is larger than\n> that. It's a less convoluted variant of the patch which was posted in the\n> above linked thread and was confirmed to prevent the starvation problem.\n> \n> But that's only to be considered the last resort because it results in an\n> insane amount of avoidable hrtimer interrupts.\n> \n> The problem of user controlled timers is that the input value is only\n> sanity checked vs. validity of the provided timespec and clamped to be in\n> the maximum allowable range. But for performance reasons for in kernel\n> usage there is no check whether a to be armed timer might have been expired\n> already at enqueue time.\n> \n> The rest of the series addresses this by providing a separate interface to\n> arm user controlled timers. This works the same way as the existing\n> hrtimer_start_range_ns(), but in case that the timer ends up as the first\n> timer in the clock base after enqueue it provides additional checks:\n> \n> - Whether the timer becomes the first expiring timer in the CPU base.\n> \n> \tIf not the timer is considered to expire in the future as there is\n> \talready an earlier event programmed.\n> \n> - Whether the timer has expired already by comparing the expiry value\n> against current time.\n> \n> \tIf it is expired, the timer is removed from the clock base and the\n> \tfunction returns false, so that the caller can handle it. That's\n> \trequired because the function cannot invoke the callback as that\n> \tmight need to acquire a lock which is held by the caller.\n> \n> This function is then used for the user controlled timer arming interfaces\n> mainly by converting hrtimer sleeper over to it. That affects a few in\n> kernel users too, but the overhead is minimal in that case and it spares a\n> tedious whack the mole game all over the tree.\n> \n> The other usage sites in posixtimers, alarmtimers and timerfd are converted\n> as well, which should cover the vast majority of user space controllable\n> timers as far as my investigation goes.\n> \n> The series applies against Linux tree and is also available from git:\n> \n> git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git hrtimer-exp-v1\n> \n> There needs to be some discussion about the scope of backporting. The first\n> patch preventing the stall is obviously a backport candidate. The remaining\n> series can be obviously argued about, but in my opinion it should be\n> backported as well as it prevents stupid or malicious user space from\n> generating tons of pointless timer interrupts.\n> \n> Thanks,\n> \n> \ttglx\n> ---\n> drivers/power/supply/charger-manager.c | 12 +-\n> fs/timerfd.c | 115 +++++++++++++++-----------\n> include/linux/alarmtimer.h | 9 +-\n> include/linux/clockchips.h | 2 \n> include/linux/hrtimer.h | 20 +++-\n> include/trace/events/timer.h | 13 +++\n> kernel/time/alarmtimer.c | 70 +++++++---------\n> kernel/time/clockevents.c | 23 +++--\n> kernel/time/hrtimer.c | 142 +++++++++++++++++++++++++++++----\n> kernel/time/posix-cpu-timers.c | 18 ++--\n> kernel/time/posix-timers.c | 35 +++++---\n> kernel/time/posix-timers.h | 4 \n> kernel/time/tick-common.c | 1 \n> kernel/time/tick-sched.c | 1 \n> net/netfilter/xt_IDLETIMER.c | 24 ++++-\n> 15 files changed, 341 insertions(+), 148 deletions(-)\n> \n>","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n secure) header.d=wbinvd.org header.i=@wbinvd.org header.a=rsa-sha256\n header.s=wbinvd header.b=W0VTYY3f;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; 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charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20260407083219.478203185@kernel.org>"}},{"id":3674329,"web_url":"http://patchwork.ozlabs.org/comment/3674329/","msgid":"<87ika24phf.ffs@tglx>","list_archive_url":null,"date":"2026-04-07T18:03:40","subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","submitter":{"id":92397,"url":"http://patchwork.ozlabs.org/api/people/92397/","name":"Thomas Gleixner","email":"tglx@kernel.org"},"content":"On Tue, Apr 07 2026 at 10:38, Calvin Owens wrote:\n> On Tuesday 04/07 at 10:54 +0200, Thomas Gleixner wrote:\n>> He provided a reproducer, which sets up a timerfd based timer and then\n>> rearms it in a loop with an absolute expiry time of 1ns.\n>\n> The original AMD machines survive the reproducer with this series.\n>\n> Tested-by: Calvin Owens \n>\n> I'm happy to test subsets of it and stable backports too, if that's\n> helpful, just let me know.\n\nWe'll only backport the first patch, so confirming that it still\nprevents the issue would be nice. The rest is slated for upstream only.\n\nThanks,\n\n tglx","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=JCAvlZFC;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; helo=sea.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11697-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"JCAvlZFC\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org [172.234.253.10])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fqvLq5h5Fz1xtJ\n\tfor ; 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a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775585024; c=relaxed/simple;\n\tbh=PCVX5+MJaDtv/5QhBK4sEVcRXCI5vHo43oyqAw9jfPE=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID:\n\t MIME-Version:Content-Type;\n b=Falfi8LjMtAq/4ZyVVggPrPtOzk6jVLakMf1JPKWnLcffE/5xPgU4WbLKWCrLZb820OG1kde5aoardJQaSJh+LK+Z2hKTbwbJL5YKymjlClGT+HZbIiasm+1vRnvwWlgt7ttwrBSzQVsBwSIfWUc9hOhuNyuYVXJ4rLBbAZ3xnk=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=JCAvlZFC; arc=none smtp.client-ip=10.30.226.201","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1775585024;\n\tbh=PCVX5+MJaDtv/5QhBK4sEVcRXCI5vHo43oyqAw9jfPE=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:From;\n\tb=JCAvlZFCbL40yalBtx+vibMzq1gI0LuOkr9zf7wT+0s9dpq0I4d5U9ZHv4rMIwoN/\n\t lOaHUp7VLggxIpmS3tjRVqJxdTCHT7rw1f0JrPRceWOXpDY8EM9v44cuLv65/1ZW6s\n\t wsBIDGdekvhUlGZneUCm68A+jviQj0jkKZJRzTh2WpKWFeO1dSoqZwi3oei5FT3Q14\n\t fcBg7ZQvEIfp0pfxLyM5NSyW2jQpLeq+NJwYCvB1rRtY1Jo0fDYfYtWd4ppviFmmkx\n\t KeBRgqZ3zbApsODuNYkbgy7xUAYpumLGGcWLLfZjLoeNTTDtxOzy/yX6OAHzAlkRAI\n\t LNHJidhDWpG+w==","From":"Thomas Gleixner ","To":"Calvin Owens ","Cc":"LKML , Peter Zijlstra\n , Anna-Maria Behnsen ,\n Frederic Weisbecker , Ingo Molnar ,\n John Stultz , Stephen Boyd ,\n Alexander Viro , Christian Brauner\n , Jan Kara ,\n linux-fsdevel@vger.kernel.org, Sebastian Reichel ,\n linux-pm@vger.kernel.org, Pablo Neira Ayuso , Florian\n Westphal , Phil Sutter ,\n netfilter-devel@vger.kernel.org, coreteam@netfilter.org","Subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","In-Reply-To":"","References":"<20260407083219.478203185@kernel.org>\n ","Date":"Tue, 07 Apr 2026 20:03:40 +0200","Message-ID":"<87ika24phf.ffs@tglx>","Precedence":"bulk","X-Mailing-List":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Type":"text/plain"}},{"id":3674349,"web_url":"http://patchwork.ozlabs.org/comment/3674349/","msgid":"","list_archive_url":null,"date":"2026-04-07T18:35:33","subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","submitter":{"id":91507,"url":"http://patchwork.ozlabs.org/api/people/91507/","name":"Calvin Owens","email":"calvin@wbinvd.org"},"content":"On Tuesday 04/07 at 20:03 +0200, Thomas Gleixner wrote:\n> On Tue, Apr 07 2026 at 10:38, Calvin Owens wrote:\n> > On Tuesday 04/07 at 10:54 +0200, Thomas Gleixner wrote:\n> >> He provided a reproducer, which sets up a timerfd based timer and then\n> >> rearms it in a loop with an absolute expiry time of 1ns.\n> >\n> > The original AMD machines survive the reproducer with this series.\n> >\n> > Tested-by: Calvin Owens \n> >\n> > I'm happy to test subsets of it and stable backports too, if that's\n> > helpful, just let me know.\n> \n> We'll only backport the first patch, so confirming that it still\n> prevents the issue would be nice. The rest is slated for upstream only.\n\nConfirmed, [1/12] alone passes.\n\nThanks,\nCalvin","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n secure) header.d=wbinvd.org header.i=@wbinvd.org header.a=rsa-sha256\n header.s=wbinvd header.b=SumApEDL;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11699-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=wbinvd.org header.i=@wbinvd.org\n header.b=\"SumApEDL\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=74.125.82.174","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=wbinvd.org","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=wbinvd.org"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org\n [IPv6:2600:3c0a:e001:db::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fqvyw50W6z1xtJ\n\tfor ; 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charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<87ika24phf.ffs@tglx>"}},{"id":3674482,"web_url":"http://patchwork.ozlabs.org/comment/3674482/","msgid":"<87fr564hef.ffs@tglx>","list_archive_url":null,"date":"2026-04-07T20:58:16","subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","submitter":{"id":92397,"url":"http://patchwork.ozlabs.org/api/people/92397/","name":"Thomas Gleixner","email":"tglx@kernel.org"},"content":"On Tue, Apr 07 2026 at 11:35, Calvin Owens wrote:\n> On Tuesday 04/07 at 20:03 +0200, Thomas Gleixner wrote:\n>> On Tue, Apr 07 2026 at 10:38, Calvin Owens wrote:\n>> > On Tuesday 04/07 at 10:54 +0200, Thomas Gleixner wrote:\n>> >> He provided a reproducer, which sets up a timerfd based timer and then\n>> >> rearms it in a loop with an absolute expiry time of 1ns.\n>> >\n>> > The original AMD machines survive the reproducer with this series.\n>> >\n>> > Tested-by: Calvin Owens \n>> >\n>> > I'm happy to test subsets of it and stable backports too, if that's\n>> > helpful, just let me know.\n>> \n>> We'll only backport the first patch, so confirming that it still\n>> prevents the issue would be nice. The rest is slated for upstream only.\n>\n> Confirmed, [1/12] alone passes.\n\nThanks a lot for all your help. Very appreciated.\n\n tglx","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=L+nE9I02;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11705-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"L+nE9I02\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fqz9r1DpVz1xv0\n\tfor ; Wed, 08 Apr 2026 07:00:32 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby tor.lore.kernel.org (Postfix) with ESMTP id 53B2130387F7\n\tfor ; Tue, 7 Apr 2026 20:58:22 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id C52B237A4AB;\n\tTue, 7 Apr 2026 20:58:20 +0000 (UTC)","from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 48671313E30;\n\tTue, 7 Apr 2026 20:58:20 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id 49A9BC116C6;\n\tTue, 7 Apr 2026 20:58:19 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775595500; cv=none;\n b=XE9gDT6iLPYV2x4HQI/oyNcv/UsKulvOg0eFKdW4OXaitPl6TaY8cZv8Vy1/aJQJDo6qLSIwUatrAsTDV/rJneqoCU1h0HkQgLoKzheiZUnXqNvQXnmsXYN6yZwT3IJ5vOZB1Hk3CG9SgsyzOfWjlU3/c313r1s/gpbED/SPqUk=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775595500; c=relaxed/simple;\n\tbh=azI9MIFpXRuzEZQXX/hxvHrFrp7m5B/1P6YlrzqI9C8=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID:\n\t MIME-Version:Content-Type;\n b=oxFdynfL5BW1sHkoQd2VvehIQTCMh84XDbchxnDBU8yT3QX248MJ62BgqeJkKmVMwbT1OHEU9AdhxIgETBOQyGs4J3RYCj1k/nTsXWldtR6hXJzJYzKtjcUW22RfhGkiLwM0LVPZpS80Vnu0XPIfGlQUmDcVc5OnbOocnhqieMI=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=L+nE9I02; arc=none smtp.client-ip=10.30.226.201","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1775595500;\n\tbh=azI9MIFpXRuzEZQXX/hxvHrFrp7m5B/1P6YlrzqI9C8=;\n\th=From:To:Cc:Subject:In-Reply-To:References:Date:From;\n\tb=L+nE9I02IxZxS4Ni9MXq6/89TVLA0jMQWLRuUe9unn2BRSZARrFeatLTGesgC0lhh\n\t FyMJhUN/9Ih6oXz6cotXiaP60n5KI+Rzfy9u7l33aqx04PY9E3mpCm3+fv8oz2x1Qm\n\t Sqixfln6WsMpm8aCtPVG8dLllQ+qHYRHdnqNInWq037b/dl2ymRLL4j8K8z6L6Feag\n\t VAvKt7nxHoocnqxTq/k2WfyprCh+TMt+G0DjeERJhF/q1FuEnP9qT4fWNIM+KCUO0V\n\t 0VgkNma4b7imM4xCsRi0Z2v1V3JyNiWidmrQ87Dth1WTKuEy/mPjRqWnkzAOwtoYfy\n\t si3zib4l86Ovg==","From":"Thomas Gleixner ","To":"Calvin Owens ","Cc":"LKML , Peter Zijlstra\n , Anna-Maria Behnsen ,\n Frederic Weisbecker , Ingo Molnar ,\n John Stultz , Stephen Boyd ,\n Alexander Viro , Christian Brauner\n , Jan Kara ,\n linux-fsdevel@vger.kernel.org, Sebastian Reichel ,\n linux-pm@vger.kernel.org, Pablo Neira Ayuso , Florian\n Westphal , Phil Sutter ,\n netfilter-devel@vger.kernel.org, coreteam@netfilter.org","Subject":"Re: [patch 00/12] hrtimers: Prevent hrtimer interrupt starvation","In-Reply-To":"","References":"<20260407083219.478203185@kernel.org>\n <87ika24phf.ffs@tglx>\n ","Date":"Tue, 07 Apr 2026 22:58:16 +0200","Message-ID":"<87fr564hef.ffs@tglx>","Precedence":"bulk","X-Mailing-List":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Type":"text/plain"}}]