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 7EC83C433EF for ; Fri, 27 May 2022 17:23:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354283AbiE0RXx (ORCPT ); Fri, 27 May 2022 13:23:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237226AbiE0RXu (ORCPT ); Fri, 27 May 2022 13:23:50 -0400 Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B35313C0A2; Fri, 27 May 2022 10:23:50 -0700 (PDT) Received: by mail-pl1-x634.google.com with SMTP id q18so4668899pln.12; Fri, 27 May 2022 10:23:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=QNE+C9LvKf6o9OSSRIZZjYit2ACDgKSqp0cFlqRQUkA=; b=Ap9vNO/0kaxbQr1Vg/t3oTPnDrIe/ot0ObxfFazJtuLCid5VwVrE5SN+hTNy+tSwlh ul2W/6ur/9+D2cmH4pQfcdPOw8HEIpFq+6DC8s0G0qhWQzL4IWY5BXkLuFhKe6BFmS3C 1Ap0CoVjGi5NXLGh3v/eT1h7/XpIxwL0ZiqL76/aXV2e0YJzrCd6ZlONbhgUgLs24Sn0 vIJjto9cAaMbshQVQ+HqQyGs14NGdfPMLR9RXRipGkmLbnSX7HSHNJDHDlw4e6h9rKYw KbQkyb8s0k8mza2dkWOjnSYImUcQkkZsIGLtmPwEl9NLbDo0AR403M8wAZgYCW4yLrwb OaHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition :content-transfer-encoding:in-reply-to; bh=QNE+C9LvKf6o9OSSRIZZjYit2ACDgKSqp0cFlqRQUkA=; b=tYIVlld4fTF0W2d8obNutjAxxmrDgsptxD2Snlni5FE+o5rDi7rMW+dl9Vj/pHTqSJ /yTWTP1rXNh24I2wgzqgSi/2ypiN7avPtZBTuuos7izdAJ2qwcHPsY0tjlFEmNZgjGGD HTkDZp+SgrcG5I1I6otTnT6O0/LBfSdgbQ05eoN8uop6K5I8NqCu2iYLsth/atbUiOfe ZKaiDL9exnrONTR4f2bj0fMI/B6rYO6Aps53dEsAtFoZBQwirf7wVTOgTmkb7/XjCbLn A54E/tWT25eN7Sx5v19yg7NpTSQ7weCh0iPfRDBV9laNXe8npqQT5vcND0jEPzywZYVb pwzQ== X-Gm-Message-State: AOAM531tKCtMOuSwUw0SJR6L2LUbsvrb0ftlstHnD7jQVVLUSBvE0KEf TqLqbECIOG6RJxfRaSS6S3Otj+09Rno= X-Google-Smtp-Source: ABdhPJztcIM5jLzkkE+h5WG0QxVIkFzyKnQa6MjuoTuKxBxwXGiTJQBgopdAb8yKfd7xuzzeiM6RIw== X-Received: by 2002:a17:902:e806:b0:163:6443:ec6a with SMTP id u6-20020a170902e80600b001636443ec6amr12431207plg.171.1653672229339; Fri, 27 May 2022 10:23:49 -0700 (PDT) Received: from localhost ([2620:10d:c090:400::4:ac0e]) by smtp.gmail.com with ESMTPSA id u3-20020a17090a3fc300b001e270cc443dsm1868801pjm.46.2022.05.27.10.23.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 May 2022 10:23:48 -0700 (PDT) Sender: Tejun Heo Date: Fri, 27 May 2022 07:23:47 -1000 From: Tejun Heo To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: Tadeusz Struk , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Zefan Li , Johannes Weiner , Bui Quang Minh Subject: Re: [PATCH 2/2] cgroup: Use separate work structs on css release path Message-ID: References: <20220525151517.8430-1-mkoutny@suse.com> <20220525151517.8430-3-mkoutny@suse.com> <20220525161455.GA16134@blackbody.suse.cz> <904ef8af-13a5-e566-b760-74519f70fa62@linaro.org> <20220527165429.GJ11007@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220527165429.GJ11007@blackbody.suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 27, 2022 at 06:54:29PM +0200, Michal Koutný wrote: > Hello Tadeusz. > > On Fri, May 27, 2022 at 09:39:20AM -0700, Tadeusz Struk wrote: > > As far as I can see we are trying to test the same thing suggested by Tejun. > > I just sent a test request to try this: > > https://github.com/tstruk/linux/commit/master > > Yup, I've added few more prints to get more fine-grained resolution. > Also, I decided to use ftrace printk not to interfere with timing too > much (due to the original race hypothesis). > > > Let me know if you have any more tests to run and I will hold off until > > you are done. > > My latest attempt is [1] (tip 5500e05d82fd5b5db2203eedb3f786857d3ccbea). > > So far, I'm not convinced, I extract the complete ftrace buffer from the > syzbot runs, so I'm not drawing any conclusions from the traces I've > got. I'm not going to continue today. You may have more luck with your > plain printk (if it's just imbalance and it avoids printk locking > sensitive paths). At least for triaging, it may be easier to use bpftrace to attach kprobes to the get/put functions with the right filter and record the kstack counts. Thanks. -- tejun