[Bug 2084233] [NEW] Excluded libaio library from mlock may hang system while removing rootfs snapshot

[Guillaume Penin]

Public bug reported:

Hi,

One of our production system hang while executing a custom backup
script, using LVM snapshots and raw copies in order to build an
alternative boot environment.

We opened an issue on the LVM2 Github
(https://github.com/lvmteam/lvm2/issues/159), and one of the contributor
advises us to use at least the LVM2 2.03.17 version, built with the
following patch :
https://github.com/lvmteam/lvm2/commit/a3eb6ba425773224076c41aabc3c490a6a016ee6

The libaio library is, on previous versions, excluded of the mlock call
and it can lead to a full system hang, specifically during a rootfs
snapshot removal, as removing a shapshot freezes the underlying volume
and the system won't be able to read on that volume during this
operation. In rare condtions, this can be harmful if the system decides
to page-out during this operation.

As I understand that it may be complicated to upgrade the LVM2 version
on stable releases of Ubuntu, is it possible to cherry-pick the relevant
(and really simple/small) patch from the LVM2 2.03.17 version on the
current LVM2 versions used by Ubuntu ?

Regards,

** Affects: lvm2
     Importance: Unknown
         Status: Unknown

** Affects: lvm2 (Ubuntu)
     Importance: Undecided
         Status: New

** Bug watch added: github.com/lvmteam/lvm2/issues #159
   https://github.com/lvmteam/lvm2/issues/159

** Also affects: lvm2 via
   https://github.com/lvmteam/lvm2/issues/159
   Importance: Unknown
       Status: Unknown

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to lvm2 in Ubuntu.
https://bugs.launchpad.net/bugs/2084233

Title:
  Excluded libaio library from mlock may hang system while removing
  rootfs snapshot

Status in lvm2:
  Unknown
Status in lvm2 package in Ubuntu:
  New

Bug description:
  Hi,

  One of our production system hang while executing a custom backup
  script, using LVM snapshots and raw copies in order to build an
  alternative boot environment.

  We opened an issue on the LVM2 Github
  (https://github.com/lvmteam/lvm2/issues/159), and one of the
  contributor advises us to use at least the LVM2 2.03.17 version, built
  with the following patch :
  https://github.com/lvmteam/lvm2/commit/a3eb6ba425773224076c41aabc3c490a6a016ee6

  The libaio library is, on previous versions, excluded of the mlock
  call and it can lead to a full system hang, specifically during a
  rootfs snapshot removal, as removing a shapshot freezes the underlying
  volume and the system won't be able to read on that volume during this
  operation. In rare condtions, this can be harmful if the system
  decides to page-out during this operation.

  As I understand that it may be complicated to upgrade the LVM2 version
  on stable releases of Ubuntu, is it possible to cherry-pick the
  relevant (and really simple/small) patch from the LVM2 2.03.17 version
  on the current LVM2 versions used by Ubuntu ?

  Regards,

To manage notifications about this bug go to:
https://bugs.launchpad.net/lvm2/+bug/2084233/+subscriptions