[Bug 1551828] Re: kpartx causes kernel oops when NVMe devices is not in blacklist

[Launchpad Bug Tracker]

This bug was fixed in the package multipath-tools - 0.4.9-3ubuntu7.11

---------------
multipath-tools (0.4.9-3ubuntu7.11) trusty; urgency=medium

  * debian/patches/series: add dm-multipath-backlist-nvme-5c412e47.patch to
    the series file; it was missing in the previous upload and thus the patch
    intending to fix bug 1551828 was not applied. (LP: #1551828)

multipath-tools (0.4.9-3ubuntu7.10) trusty; urgency=medium

  [ Mathieu Trudel-Lapierre ]
  * debian/patches/dm-multipath-backlist-nvme-5c412e47.patch: blacklist NVMe
    from multipath, otherwise kpartx calls will hang. This is because mpath
    works at the request level (which NVMe bypasses), so multipathing is not
    supported on NVMe. (LP: #1551828)

  [ Mauricio Faria de Oliveira ]
  * Remove partition device nodes of individual paths (for LVM on multipath)
    (LP: #1540401)
    - debian/multipath-tools.dm-mpath-lvm.udev: udev rule for that.
    - debian/initramfs/hooks: copy the udev rule and partx to the initramfs.
    - debian/initramfs/init-top: load dm-multipath module for 'multipath -c'.
    - debian/rules: install the udev rule and init-top.

 -- Mathieu Trudel-Lapierre <mathieu-tl at ubuntu.com>  Mon, 21 Mar 2016
10:41:36 -0400

** Changed in: multipath-tools (Ubuntu Trusty)
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1551828

Title:
  kpartx causes kernel oops when NVMe devices is not in blacklist

Status in multipath-tools package in Ubuntu:
  Fix Released
Status in multipath-tools source package in Trusty:
  Fix Released

Bug description:
  [Impact]
  Users expecting to use multipath over NVMe device will notice hangs with any software attempting to use the device-mapper devices (/dev/dm-* or /dev/mapper/mpath*).

  [Test case]
  1) Setup multipath over nvme. (should not be possible with the patch in)
  2) Run kpartx -av /dev/dm-device-mulipath-over-nvme   (will hang without the patch)

  [Regression Potential]
  Minimal. This removes a theoretically valid use case of multipath devices using NVMe disks, which is not technically supported and leads to software hangs (and thus installs will not complete, and setting up multipath over NVMe post-install would hang).
  This only affects nvme devices; so any storage device using the "nvme" naming would no longer be able to setup multipath even if technical specifications were to change sufficiently to support multipath over NVMe (or if some other device starts using this naming which isn't affected by the same limitations).

  
  -----

  When on bare metal uses NVMe devices - kpartx cause kernel oops.
  http://paste.openstack.org/show/488638/

  Also any tools which works with disks (e.g. fdisk, lsblk) hangs in D state (uninterruptible sleep) while trying to to read /dev/dm-X.
  This bug is already described and fixed in upstream (http://git.opensvc.com/gitweb.cgi?p=multipath-tools/.git;a=commitdiff;h=5c412e47e589b5325ed7de6cba86d906a671d9df)

  I made patches for trusty and xenial versions of multipath-tools.
  Patches which fix issue is in attach.
  Could you apply this patches please, at least for trusty version?

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