nscd should not cache netgroups by default
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
eglibc (Ubuntu) |
Fix Released
|
Medium
|
Adam Conrad | ||
Precise |
Fix Released
|
Medium
|
Adam Conrad | ||
Quantal |
Fix Released
|
Undecided
|
Adam Conrad |
Bug Description
[Impact / Justification]
The new netgroup caching feature seems to be plagued with issues, including random segfaults, and just plain not returning useful results, depending on your test bed. This patch doesn't address any of the actual issues, but just disabled netgroup caching in the default /etc/nscd.conf to discourage its use.
[Test Case]
Check after upgrade or fresh install that /etc/nscd.conf has netgroup caching disabled. This being a dpkg conffile, it won't be changed if you've modified it locally.
[Regression Potential]
Disabling a broken feature doesn't likely have much regression potential. We got here after spending a great deal of time trying to debug all the breakages with someone who was trying to use it, so I'm unconvinced anyone's using it successfully.
[Original Report]
Netgroup caching is a rather new feature of nscd. It only entered the eglibc source tree late last year and the first upstream release of nscd to include netgroup caching was on March 21, 2012 [1]. Thus, it's is a feature that is not likely deployed at any significant scale anywhere currently. And so it has poor general test coverage.
We have reports that this feature either segfaults nscd [1] or that even when it doesn't crash, the feature still doesn't work [2].
The "enabled" setting is inherited from upstream, but I think at least for precise, we should default to disabled.
tags: | added: precise |
Changed in eglibc (Ubuntu): | |
assignee: | nobody → Adam Conrad (adconrad) |
Changed in eglibc (Ubuntu Precise): | |
assignee: | nobody → Adam Conrad (adconrad) |
Changed in eglibc (Ubuntu Precise): | |
importance: | Undecided → Medium |
Changed in eglibc (Ubuntu): | |
importance: | Undecided → Medium |
Changed in eglibc (Ubuntu): | |
status: | New → Fix Committed |
description: | updated |
Changed in eglibc (Ubuntu Quantal): | |
assignee: | nobody → Adam Conrad (adconrad) |
This bug was fixed in the package eglibc - 2.16-0ubuntu7
---------------
eglibc (2.16-0ubuntu7) raring; urgency=low
* Merge with 2.16-0experimental1 from Debian, bringing in my tests/control syntax for autopkgtest (LP: #1081500) local-disable- nscd-netgroup- caching. diff to malloc- deadlock. diff from upstream to prevent
upstream version of the C++ header autodetection patch, some
packaging and upgrade fixes, and reducing our delta further.
* Fix debian/
* Add patch ubuntu/
disable netgroup caching in the default config (LP: #1068889)
* Backport any/cvs-
glibc deadlocking in mallock arena retry paths (LP: #1081734)
-- Adam Conrad <email address hidden> Sun, 25 Nov 2012 19:00:46 -0700