Bug#864352: lvm2: udev pvscan hang with many devices

[Marc Lehmann]

Package: lvm2
Version: 2.02.168-2
Severity: normal

Dear Maintainer,

I have a backup system with 24 or so disks. After boot, we have a lot of lvm processes hanging:

           ├─systemd-udevd(154)───lvm(425)
           ├─systemd-udevd(155)───lvm(417)
           ├─systemd-udevd(156)───lvm(424)
           ├─systemd-udevd(157)───lvm(420)
           ├─systemd-udevd(158)───lvm(423)
           ├─systemd-udevd(160)───lvm(427)
           ├─systemd-udevd(161)───lvm(428)
           ├─systemd-udevd(162)───lvm(421)
           ├─systemd-udevd(163)───lvm(422)
           ├─systemd-udevd(166)───lvm(397)
           ├─systemd-udevd(167)───lvm(426)
           ├─systemd-udevd(168)───lvm(400)
           ├─systemd-udevd(169)───lvm(429)
           ├─systemd-udevd(170)───lvm(418)
           ├─systemd-udevd(171)───lvm(413)
           ├─systemd-udevd(172)───lvm(419)

  397 ?        S      0:00      0  1623 32608  6840  0.0 /sbin/lvm pvscan --cache --activate ay --major 65 --minor 16
  400 ?        S      0:00      0  1623 32620  6804  0.0 /sbin/lvm pvscan --cache --activate ay --major 65 --minor 32
  413 ?        S      0:00      0  1623 32608  6844  0.0 /sbin/lvm pvscan --cache --activate ay --major 65 --minor 48
  417 ?        S      0:00      0  1623 32632  6816  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 160
  418 ?        S      0:00      0  1623 32616  6792  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 112
  419 ?        S      0:00      0  1623 32636  6820  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 176
  420 ?        S      0:00      0  1623 32648  6832  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 192
  421 ?        S      0:00      0  1623 32652  6824  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 80
  422 ?        S      0:00      0  1623 32660  6840  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 224
  423 ?        S      0:00      0  1623 32656  6888  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 240
  424 ?        S      0:00      0  1623 32656  6840  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 208
  425 ?        S      0:00      0  1623 32656  6876  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 128
  426 ?        S      0:00      0  1623 32656  6840  0.0 /sbin/lvm pvscan --cache --activate ay --major 65 --minor 64
  427 ?        S      0:00      0  1623 32660  6884  0.0 /sbin/lvm pvscan --cache --activate ay --major 65 --minor 0
  428 ?        S      0:00      0  1623 32656  6880  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 96
  429 ?        S      0:00      0  1623 32660  6880  0.0 /sbin/lvm pvscan --cache --activate ay --major 8 --minor 144

strace'ing any of them shows them hanging in "semop":

   semop(262144, [{0, 0, 0}], 1

Waiting for more then 15 minutes does not help, and some other subsequent
lvm commands that are manually entered also hang. killall -9 lvm kills
them and allows the system to proceed, but is, of course, not a solution.

-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64
 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.4.47-040447-generic (SMP w/8 CPU cores)
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/bash
Init: systemd (via /run/systemd/system)

Versions of packages lvm2 depends on:
ii  dmeventd                  2:1.02.137-2
ii  dmsetup                   2:1.02.137-2
ii  init-system-helpers       1.48
ii  libblkid1                 2.29.2-1
ii  libc6                     2.24-10
ii  libdevmapper-event1.02.1  2:1.02.137-2
ii  libdevmapper1.02.1        2:1.02.137-2
ii  liblvm2app2.2             2.02.168-2
ii  libreadline5              5.2+dfsg-3+b1
ii  libudev1                  232-23
ii  lsb-base                  9.20161125

lvm2 recommends no packages.

Versions of packages lvm2 suggests:
ii  thin-provisioning-tools  0.6.1-4+b1

-- Configuration Files:
/etc/lvm/lvm.conf changed [not included]

-- debconf information excluded