[Bug 818177] Re: boot failures caused by udev race

[Steve Langasek]

Looking at bugs on lvm2 turns up this gem in bug #802626:

> Just a wild speculation, because I haven't yet digged into the interactions between kernel
> and udevd, but the semaphore decrementation event might be lost when transitioning from
> the initrd-udevd to the rootfs-udevd.

In cases where people are seeing initrd problems and lvm is in use, are
there always LVM VGs *other* than for the root fs?  If there's a VG
that's not a dependency of the rootfs, then indeed the vgchange call can
be racing the main initramfs sequence.

Twiddling the lvm2 package to insert a delay may help with reproducing
the issue.

None of this explains any issues with device nodes being absent from
/dev on the root filesystem when lvm is *not* in use.  The original bug
report did not mention LVM at all.  Can someone comment on the disk
configuration used there?  Maybe we need to split this into two bugs.

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https://bugs.launchpad.net/bugs/818177

Title:
  boot failures caused by udev race

Status in “linux” package in Ubuntu:
  Invalid
Status in “udev” package in Ubuntu:
  Confirmed
Status in “linux” source package in Oneiric:
  Invalid
Status in “udev” source package in Oneiric:
  Confirmed

Bug description:
  After running a do-release-upgrade -d on a natty server, I'm unable to
  boot the machine properly.

  It looks like it doesn't see the local disks anymore.

  I think this looks quite a lot like the debbug linked from here:
  https://bugs.launchpad.net/ubuntu/oneiric/+source/linux/+bug/746751

  ProblemType: Bug
  DistroRelease: Ubuntu 11.10
  Package: linux-image-3.0.0-7-server 3.0.0-7.8
  ProcVersionSignature: Ubuntu 3.0.0-7.8-server 3.0.0
  Uname: Linux 3.0.0-7-server x86_64
  AlsaDevices:
   total 0
   crw-rw---- 1 root audio 116,  1 2011-07-29 13:34 seq
   crw-rw---- 1 root audio 116, 33 2011-07-29 13:34 timer
  AplayDevices: Error: [Errno 2] No such file or directory
  Architecture: amd64
  ArecordDevices: Error: [Errno 2] No such file or directory
  AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
  CRDA: Error: [Errno 2] No such file or directory
  Date: Fri Jul 29 13:40:10 2011
  HibernationDevice: RESUME=UUID=844d17fa-ff69-4250-844b-33b930236c56
  IwConfig:
   lo        no wireless extensions.
   
   eth0      no wireless extensions.
   
   eth1      no wireless extensions.
  MachineType: HP ProLiant DL380 G5
  PciMultimedia:
   
  ProcEnviron:
   LANGUAGE=en_US:
   PATH=(custom, user)
   LANG=en_US
   SHELL=/bin/bash
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.0.0-7-server root=/dev/mapper/User Name-root ro INIT_VERBOSE=yes
  RelatedPackageVersions:
   linux-restricted-modules-3.0.0-7-server N/A
   linux-backports-modules-3.0.0-7-server  N/A
   linux-firmware                          1.56
  RfKill: Error: [Errno 2] No such file or directory
  SourcePackage: linux
  UpgradeStatus: Upgraded to oneiric on 2011-07-29 (0 days ago)
  dmi.bios.date: 06/28/2007
  dmi.bios.vendor: HP
  dmi.bios.version: P56
  dmi.chassis.type: 23
  dmi.chassis.vendor: HP
  dmi.modalias: dmi:bvnHP:bvrP56:bd06/28/2007:svnHP:pnProLiantDL380G5:pvr:cvnHP:ct23:cvr:
  dmi.product.name: ProLiant DL380 G5
  dmi.sys.vendor: HP

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