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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 C388AECE566 for ; Fri, 21 Sep 2018 13:18:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CAFF21523 for ; Fri, 21 Sep 2018 13:18:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="AEcfrXbn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5CAFF21523 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389970AbeIUTH0 (ORCPT ); Fri, 21 Sep 2018 15:07:26 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:41743 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728098AbeIUTH0 (ORCPT ); Fri, 21 Sep 2018 15:07:26 -0400 Received: by mail-ed1-f66.google.com with SMTP id f38-v6so10699572edd.8; Fri, 21 Sep 2018 06:18:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:reply-to:from:date:message-id:subject:to:cc; bh=fSRwvwhOM0DKy71IgTaPgffXf+6iMoKDxt2k6I15FTE=; b=AEcfrXbnBy5AUFvarIpUgzacXp5/YWqVxLVHnBaQZaroY7uOKKAVi5dTAVD35ZqQuJ 9ZQ7b1xtjdiWy6A3f5ec7vqorFfJsFW1xQQYfQtiiUsaZRiE1NrgVez4B3vO+Wzke8Dz JUiH8j9e0yfsbxMHrUgy2R9b+QzxtTQYUqC/SyXKjXU1u05RV2fNhkkOu7+KYncb1X6o Ww6Zl8IXJdhXI1Ane3EU/xysqamiY3YkkGNsr7XqgzZfXrncerW/q4Ga57TrYixFmZf1 qGvDSIv2cLTOAYPEazqj3/cqGnqP8694+S2qq4eBSUYCevJOJei5fGG5dwwSx3h3YXEi poZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:reply-to:from:date:message-id :subject:to:cc; bh=fSRwvwhOM0DKy71IgTaPgffXf+6iMoKDxt2k6I15FTE=; b=MZ98LoAGcepa9fzBqpDWoGT5Mleugd9uzt4rNHob2DVmEZehcvQX5IjLoFzb/1aCt/ yR+i8bj+NGvptu8T35X5PvMoy9Un57a4ZnfQOnqfbfS5sMoF7RW4BqsDjWJXBOzaOydw y44Nf4a/dfuEpqswHmgK9rpBAsG4LrmYz98SM0ArUsJNCpcwO5mkSAO86//BQ1kXvB4w WXYqViQOF8FFgcikdKxkQTJK8IGEkdn9Z+BOfpswCfV/12QVGbjMRj6F9DJ0WhFnUGzV +EsO0GCeMyVYH2EcLIjx6TimiJ+/8n80YdeNwUi9zvFo0Px2DJilNVRfS1L5AzYbACxq OjYw== X-Gm-Message-State: APzg51AY6qqCh6hZ5ld0O0vCeknU8dII0ehqSs+g6VQvL1Pse0tFj0BJ qNHE9CYEClyULuR9bhHiXPnqp/Y4HvnPQIiNLa/JnSAT X-Google-Smtp-Source: ANB0VdZu+LVCDutMGC9UgeG8i9oJsUb18Lj7GKS/RrJ6G30TNiZ+ZbM3USq+DNa4nwlQz0BXS9UrfxZ5cXjmrqFdm1E= X-Received: by 2002:a50:baae:: with SMTP id x43-v6mr11836545ede.65.1537535914805; Fri, 21 Sep 2018 06:18:34 -0700 (PDT) MIME-Version: 1.0 Reply-To: mtk.manpages@gmail.com From: "Michael Kerrisk (man-pages)" Date: Fri, 21 Sep 2018 15:18:23 +0200 Message-ID: Subject: Cgroup v2 bug: "domain invalid" node can't be converted to "threaded" To: Tejun Heo Cc: lkml , "open list:CONTROL GROUP (CGROUP)" , "Serge E. Hallyn" , Amin Jamali , Joao De Almeida Pereira Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Tejun, While experimenting with cgroups, we've found what looks to be a bug. I eventually simplified this to what I think are the minimum steps to demonstrate the issue. The following shell session demonstrates the issue: [Kernel was booted with cgroup_no_v1=all] # cd /sys/fs/cgroup/unified # cat cgroup.subtree_control # show that no controllers are enabled # mkdir -p mycgrp/a/b/c # echo threaded > mycgrp/a/b/cgroup.type At this point, the hierarchy looks as follows: mycgrp [d] a [dt] b [t] c [inv] Now let's make node "a" threaded (and thus "mycgrp" s made "domain threaded"): # echo threaded > mycgrp/a/cgroup.type By this point, we now have a hierarchy that looks as follows: mycgrp [dt] a [t] b [t] c [inv] But, when we try to convert the node "c" from "domain invalid" to "threaded", we get ENOTSUP on the write(): # echo threaded > mycgrp/a/b/c/cgroup.type sh: echo: write error: Operation not supported Your thoughts? Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/