[Bug 672177] Re: libc6 upgrade causes umount to fail on shutdown because init cannot be restarted

[Scott James Remnant]

Are you sure?  I can't find that code at all - it looks like it's been
lost somehow

On Tue, Dec 28, 2010 at 6:19 PM, Clint Byrum <clint at fewbar.com> wrote:
> On Tue, 2010-12-28 at 14:22 +0000, Scott James Remnant wrote:
>> On Tue, Dec 28, 2010 at 6:47 AM, Clint Byrum <clint at fewbar.com> wrote:
>>
>> > This makes sense, because telinit u just sends SIGTERM to upstart, which
>> > has no handler, as it was removed by revision 977, and doesn't seem to
>> > have been added back. Since SIG_DFL signals are not delivered to init,
>> > I'm not sure how umountroot's call to 'telinit u' can help in this case.
>> >
>> > Unless I'm missing something in upstart's code (quite likely) I think
>> > there may still potentially need to be a change in upstart to support
>> > re-executing.
>> >
>> Hmm, while that handled was removed Upstream, the code should have
>> been retained in the Ubuntu package as part of the "telinit u" patch.
>>
>> The idea is that rather than doing a full state transfer, Upstart just
>> re-exec's itself and loses all state.  That's why we do it as the last
>> thing before unmounting the root on shutdown, because it then doesn't
>> matter about the state - there shouldn't be any.
>>
>> Maybe that part of the patch has been lost?
>>
>
> Ahh, as I suspected I was missing something in upstart's code.
>
> That code is cleverly hidden within the package diff.
>
> It registers nih_main_term_signal() which calls nih_main_loop_exit(),
> which tells init to exit after any currently running operation is over.
>
> So, it would seem init exits on SIGTERM. I did see it actually exit and
> end up panicing the kernel once, but only when I sent multiple kills.
>
> init should never exit, so should'nt we instead be execcing ourselves
> again? Will keep digging in, maybe neither are happening as we expect
> them to, causing this issue.
>
> --
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> https://bugs.launchpad.net/bugs/672177
>
> Title:
>  libc6 upgrade causes umount to fail on shutdown because init cannot be restarted
>
> Status in Upstart:
>  Invalid
> Status in “eglibc” package in Ubuntu:
>  Invalid
> Status in “upstart” package in Ubuntu:
>  Confirmed
>
> Bug description:
>  On a clean install of Ubuntu 10.04.1, after upgrading the offer libc6 upgrade, on the next reboot the root fs can't be properly unmounted (mount: / is busy). This causes fsck to run on boot and of course some minor issues with the filesystem. This might not be a problem with libc6 itself, but a side effect of upgrading in combination with some other package (I suspect the init process, so I guess upstart).
>
> The fsck run, and the orphaned inodes it finds are holding me back from installing this on a new server - especially since this already happens on a clean install of 10.04.1!
>
> paul at ubuntu:~$ lsb_release -rd
> Description:    Ubuntu 10.04.1 LTS
> Release:        10.04
>
> ii  libc6                           2.11.1-0ubuntu7.2                 Embedded GNU C Library: Shared libraries
>
> ProblemType: Bug
> DistroRelease: Ubuntu 10.04
> Package: libc6 2.11.1-0ubuntu7.2
> ProcVersionSignature: Ubuntu 2.6.32-24.39-server 2.6.32.15+drm33.5
> Uname: Linux 2.6.32-24-server x86_64
> Architecture: amd64
> Date: Sun Nov  7 16:17:07 2010
> InstallationMedia: Ubuntu-Server 10.04.1 LTS "Lucid Lynx" - Release amd64 (20100816.2)
> ProcEnviron:
>  PATH=(custom, no user)
>  LANG=en_US.UTF-8
>  SHELL=/bin/bash
> SourcePackage: eglibc
>
>
>

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https://bugs.launchpad.net/bugs/672177

Title:
  libc6 upgrade causes umount to fail on shutdown because init cannot be restarted