From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [CFT][PATCH 09/10] sysfs: Create mountpoints with sysfs_create_empty_dir Date: Tue, 11 Aug 2015 16:11:55 -0400 Message-ID: References: <87pp63jcca.fsf@x220.int.ebiederm.org> <878ucrhxi9.fsf@x220.int.ebiederm.org> <20150811184426.GH23408@mtj.duckdns.org> <877fp1hcuj.fsf@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Linux API , Linux Containers , Greg Kroah-Hartman , Andy Lutomirski , Kenton Varda , Michael Kerrisk-manpages , Richard Weinberger , LINUXFS-ML To: "Eric W. Biederman" Return-path: In-Reply-To: <877fp1hcuj.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org Hey, On Tue, Aug 11, 2015 at 2:57 PM, Eric W. Biederman wrote: >> So, this somehow ends up confusing upstart on centos6 based systems >> making it fail to mount tmpfs on /sys/fs/cgroup. It also skips sunrpc >> and other mounts are different too. No idea why at this point. Can >> we please revert this from -stable until we know what's going on? > > *Boggle* > > The only time this should prevent anything is when in a container when > you are not global root. And then only mounting sysfs should be > affected. This is just plain boot. No namespace involved. > The only difference in executed code really should be setting an extra > flag on the kernfs, inode. The kernfs changes will also refuse to add > entries to these directories (but these directories are empty). Why do we have this in -stable then? Is this part of a larger fix? > If this is causing problems I don't have a problem with a revert but > reverts take a minute, and this seems to be the first report of this > kind. Can we take a minute and attempt to get a coherent explanation. > > From what little information you given above it sounds like something > shifted and when you rebuilt the kernel and now a memory stomp is > hitting something else. It should be a matter of moments to debug this I don't think it's a random memory stomping thing. I reverted the commit from two different kernels and the result was always consistent. > issue (once a test environment is setup), and see what is wrong and then > we can act intelligently. Tracing a single system call is not difficult. I'm already out today so it'll have to wait till tomorrow. > If there really is some weird issue I want to know what it is. Sure, but you wanna do that in -stable? Thanks. -- tejun