tar -x sometimes fails on overlayfs
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Undecided
|
Daniel Axtens | ||
Xenial |
Fix Released
|
Medium
|
Unassigned | ||
Zesty |
Fix Released
|
Medium
|
Unassigned |
Bug Description
[SRU Justification]
[Impact]
A user is seeing failures from extracting tar archives on overlay filesystems on the 4.4 kernel in constrained environments. The error presents as:
`tar: ./deps/0/bin: Directory renamed before its status could be extracted`
Following this thread (http://
Further testing showed that when setting `/proc/
The error cannot be reproduced on a 4.13 kernel, due to the series at https:/
[Fix]
For Zesty, backport the entire series.
For Xenial, where a full backport is not feasible, backport the key commit and the short list of dependencies.
[Testcase]
# Testing this bug
The testcase for this particular bug is simple - create an overlay filesystem with all layers on the same underlying file system, and then see if the inode of a directory is constant across dropping the caches:
mkdir -p /upper/upper /upper/work /lower
mount -t overlay none /mnt -o lowerdir=
cd /mnt
mkdir a
stat a # observe inode number
echo 2 > /proc/sys/
stat a # compare inode number
If the inode number is the same, the fix is successful.
# Regression testing
I have run the unionmount test suite from http://
(The series cover letter mentions a fork of the test suite at https:/
[Regression Potential]
As this changes overlayfs, there is potential for regression in the form of unexpected breakages to overlaysfs behaviour.
I think this is adequately addressed by the regression testing.
One option to reduce the regression potential on Zesty is to reduce the set of patches applied - rather than including the whole series we could include just the patches to solve this bug, which are much easier to inspect for correctness.
CVE References
Changed in linux (Ubuntu Xenial): | |
importance: | Undecided → Medium |
status: | New → Fix Committed |
Changed in linux (Ubuntu Zesty): | |
importance: | Undecided → Medium |
status: | New → Fix Committed |
tags: |
added: verification-done-xenial verification-done-zesty removed: verification-needed-xenial verification-needed-zesty |
Changed in linux (Ubuntu): | |
status: | Confirmed → Fix Released |
This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification- needed- xenial' to 'verification- done-xenial' . If the problem still exists, change the tag 'verification- needed- xenial' to 'verification- failed- xenial' .
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.
See https:/ /wiki.ubuntu. com/Testing/ EnableProposed for documentation how to enable and use -proposed. Thank you!