[Bug 1883025] Re: [focal SRU] davfs2 unable to unmount: segfault error 4 in libc.so

Rolf Leggewie 1883025 at bugs.launchpad.net
Sat Apr 24 18:46:45 UTC 2021

Am I the only one to think that Ubuntu is slowly collapsing under the
weight of its self-inflicted bureaucracy?

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  [focal SRU] davfs2 unable to unmount: segfault error 4 in libc.so

Status in davfs2 package in Ubuntu:
  Fix Released
Status in davfs2 source package in Focal:

Bug description:

  umount.davfs consistently segfault in focal.  This leads to a number
  of medium severity issues.

  - inability to unmount (this might have security implications)
  - inability to remount
  - autofs fails to unmount
  - reports of higher load in multi-user environments
  - computer "hangs" on shutdown waiting for successful umount completion


  No need for a specific test case, simply mount a resource via
  davfs2.mount.  Calling umount.davfs2 on that mount in focal will
  result in a segfault every time.  Exit code 255 and failure is
  recorded in syslog.  The mount stays mounted.

  To verify the fix from #2 which is the backport of the fix from
  upstream, simply recompile davfs2 and try the procedure once more to
  see if the problem has been solved.


  I will leave this mostly to others to evaluate.  Currently,
  umount.davfs2 is completely dysfunctional so it's hard to imagine a
  regression for a binary that isn't doing anything except segfaulting.

  [racb] Code that parses its own pidfile is being fixed. It was
  segfaulting before, so as mentioned it is unlikely to break further as
  a cause of this patch, except the normal latent bug being exposed on
  rebuild risk. If there is a problem with the pidfile parsing being
  introduced, then code further down this path could break.


  groovy and later versions have already been fixed via a new upstream
  release.  Upstream discussion of the a and m mixup can be found at the
  links below.  Duplicate bug 1859293 also has some very good


  I am getting segfaults everytime I want to unmount my webdav online-
  space (segfault error 4).

  Hardware failure is impossible as I see - because error already reported on project page (and fixed).
  Error should be fixed in davfs 1.5.6 (Maybe easiest to bump to version 1.5.6 on ubuntu repos ?) :)

  See (line 4-6):

  See 2:

  EDIT: Using Ubuntu 20.04 x64

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