Bug#803476: lvm2: lvchange hangs during initramfs local-top/lvm2 with latest udev

[Ian Campbell]

Package: lvm2
Version: 2.02.127-1
Severity: important
File: /usr/share/initramfs-tools/scripts/local-top/lvm2

Dear Maintainer,

After upgrading to latest Sid my QNAP TS-419 failed to boot.

By breaking into the initramfs shell I figured out that local-top/lvm2 
was hanging in lvchange_activate(). Running the same command manually 
from the initramfs shell prompt also resulted in a hang:

lvm lvchange -ddddddd -aay -y --sysinit --ignoreskippedcluster /dev/qnap-vg
  lvmetad is not active yet, using direct activation during sysinit
[  132.878220] device-mapper: uevent: version 1.0.3
[  132.887704] device-mapper: ioctl: 4.33.0-ioctl (2015-8-18)
initialised: dm-devel at redhat.com
<hang>

There aren't many tools in the initramfs to help debug this, but Sysrq-T 
showed:

[  186.603029] lvm             S c036e5a8     0   134    128 0x00000000
[  186.609431] [<c036e5a8>] (__schedule) from [<c036e7a0>] (schedule+0xa8/0xb8)
[  186.616511] [<c036e7a0>] (schedule) from [<c01646ec>] (SyS_semtimedop+0x514/0x76c)
[  186.624113] [<c01646ec>] (SyS_semtimedop) from [<c000a2e0>] (ret_fast_syscall+0x0/0x38)

Which seems to suggest that it is waiting for some event which 
presumably never occurs (I've left it for several hours).

I have narrowed this down to upgrading libudev0 and udev to the Stretch 
version. If I downgrade only those to the Jessie version then the 
problem no longer occurs. I've filed this against lvm2 firse since it 
supplies the script, but maybe this belongs to udev.

Ian.

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'stable-updates'), (500, 'unstable'), (500, 'stable')
Architecture: armel (armv5tel)

Kernel: Linux 4.2.0-1-kirkwood
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages lvm2 depends on:
ii  dmeventd                  2:1.02.104-1
ii  dmsetup                   2:1.02.104-1
ii  init-system-helpers       1.24
ii  initscripts               2.88dsf-59.2
ii  libc6                     2.19-22
ii  libdevmapper-event1.02.1  2:1.02.104-1
ii  libdevmapper1.02.1        2:1.02.104-1
ii  liblvm2app2.2             2.02.127-1
ii  libreadline5              5.2+dfsg-3
pn  libudev1                  <none>
ii  lsb-base                  9.20150917

lvm2 recommends no packages.

Versions of packages lvm2 suggests:
pn  thin-provisioning-tools  <none>

-- no debconf information