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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96EE2C072A2 for ; Sun, 19 Nov 2023 15:05:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231298AbjKSPFj (ORCPT ); Sun, 19 Nov 2023 10:05:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229715AbjKSPFh (ORCPT ); Sun, 19 Nov 2023 10:05:37 -0500 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C421139; Sun, 19 Nov 2023 07:05:33 -0800 (PST) Received: by mail-pl1-x629.google.com with SMTP id d9443c01a7336-1cc34c3420bso26576695ad.3; Sun, 19 Nov 2023 07:05:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1700406333; x=1701011133; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=ZunorBu+pSlhXgVxLKtqIO/zrvDIVnpRCfzitU3U4Kw=; b=RE6e3UU9As7x4DWzgzlHI0dbeoeAUfZPOW5W8wGDkcfA8ColiCtGruOh732B1XNSLy B8GPmbUL5zenValbIWl6vpSgxNDOh2dex+yGfih+pO3D0M+sF+dQBaCFh+KDb/oKnSEa lD3vy2VgpI4Je4NHgO/pP5JV9gf0pJKfBB9QFxnMCjIo9+TDrdYdpP/Jt2eopYrktsvr 9u+VG7cnJfM/LLiG/A9kIW7hAN3b1m0scsTU7HhwCYk/xydPXoy5Y303pHvdH47KNWiW /Zn+iammuv6SIhoLpjl3rjm0P8pJHgr2/6a6n6UKO/amdj4dwI6EgXMxdLVkomzN5SfI V71w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700406333; x=1701011133; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ZunorBu+pSlhXgVxLKtqIO/zrvDIVnpRCfzitU3U4Kw=; b=efhM0pQ9thQmUBycdoT5PkVtJJNUUdMLLej1ezFos9U0S+BwevgRh+YYCJDX9OM1nG FLEbSgFWUD7nftgWpjbJgsq7yICmSsCPECWHSOsfLEqG5eA09Dm8Y57FvU/wa+bFstGY PMccIU2IkhRsz8l3H1Pyab3aNYH5CdyueR6RiGKMoDraa436JOtM6apih2brxlGVBO2U eG+J5ZAhDo5FKZPlAZuKPyKMs0VDD/GA1NA0XJ/w4ijdmNAEpteeLfLREYqRgi6f5VJW dF3iJIOgRb8qUhPAuSU/yKkNxNtZ2IyyWMn3EyJlxl+JwbsOLOk035LYVY3YPXFx6HDd I9jA== X-Gm-Message-State: AOJu0YxnYD/LC+DSVOEEbyek172eUdS8YavjsErrflJleqPcj+Vd7P1j ULcK8qZVteTlnS+wxy+oAW0= X-Google-Smtp-Source: AGHT+IGzH+/CjsKrHeKApvx47z5slzIAxpySHaRmP6Ect4tge+175o42wM4woX0wpMZ83M9ABOnGYA== X-Received: by 2002:a17:902:e808:b0:1cf:5cb5:95c1 with SMTP id u8-20020a170902e80800b001cf5cb595c1mr476278plg.37.1700406332426; Sun, 19 Nov 2023 07:05:32 -0800 (PST) Received: from localhost (dhcp-72-253-202-210.hawaiiantel.net. [72.253.202.210]) by smtp.gmail.com with ESMTPSA id c8-20020a170902d48800b001ce5b6de75esm4417057plg.160.2023.11.19.07.05.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Nov 2023 07:05:32 -0800 (PST) Sender: Tejun Heo Date: Sun, 19 Nov 2023 05:05:31 -1000 From: Tejun Heo To: Tim Van Patten Cc: LKML , markhas@google.com, Tim Van Patten , Johannes Weiner , Zefan Li , cgroups@vger.kernel.org Subject: Re: [PATCH] cgroup_freezer: cgroup_freezing: Check if not frozen Message-ID: References: <20231115162054.2896748-1-timvp@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231115162054.2896748-1-timvp@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 15, 2023 at 09:20:43AM -0700, Tim Van Patten wrote: > From: Tim Van Patten > > __thaw_task() was recently updated to warn if the task being thawed was > part of a freezer cgroup that is still currently freezing: > > void __thaw_task(struct task_struct *p) > { > ... > if (WARN_ON_ONCE(freezing(p))) > goto unlock; > > This has exposed a bug in cgroup1 freezing where when CGROUP_FROZEN is > asserted, the CGROUP_FREEZING bits are not also cleared at the same > time. Meaning, when a cgroup is marked FROZEN it continues to be marked > FREEZING as well. This causes the WARNING to trigger, because > cgroup_freezing() thinks the cgroup is still freezing. > > There are two ways to fix this: > > 1. Whenever FROZEN is set, clear FREEZING for the cgroup and all > children cgroups. > 2. Update cgroup_freezing() to also verify that FROZEN is not set. > > This patch implements option (2), since it's smaller and more > straightforward. > > Signed-off-by: Tim Van Patten Applied to cgroup/for-6.7-fixes. Thanks. -- tejun