[Bug 999915] [NEW] High CPU usage on broken request to apt-cacher-ng

[Launchpad Bug Tracker]

You have been subscribed to a public bug by Chris J Arges (arges):

I manage a server with apt-cacher-ng, I noted an CPU increase to 100%
usage without any aparent reason, it sometimes even freezes so I have to
restart the service every time this happen, but sometimes this was about
twice a day...

I decided to debug it to see what was happening so I follow the steps in
http://www.unix-ag.uni-kl.de/~bloch/acng/html/troublefaq.html in the
point 9.5, I compiled the source with DEBUG flag and run it.

The next day I ended with a 2.8GB apt-cacher.err and a infinite loop of:
- target: ooo vs archive.ubuntu.com, ports: 80 vs 80, good config: 0 [139752724489984 at dlcon.cc:831|139753806664752]
- >> dlcon::SetupJobConfig [139752724489984 | 139753806664752]
- << dlcon::SetupJobConfig [139752724489984 | 139753806664752]

Some time ago the desktops computers where configured using the following source line:
deb http://serverip:3142/ooo hardy main
/ooo was an alias to a ppa, the alias was removed from the server, and all the new desktops where configured using Acquire::http { Proxy "http://servername:3142"; };
but some of the older machines keep the old format...

I attach a fragment of the log where it start the infinite loop, note
the time... it's an 8 seconds fragment log with 130500+ lines.

I have tracked the computer that was sending the request and change the
source.list, but this should be fixed in apt-cacher-ng, and handle the
request a little more graceful.

--

SRU Justification:

[Impact]
* Users of apt-cacher-ng may see CPU usage of 100% due to a infinite loop in the code.
* The fix for this package is already present in quantal and beyond, and the author has provided the patch on this bug.

[Test Case]
Use apt-cacher-ng and occasionally one may hit this infinite loop error depending on the source.list configuration.

[Regression Potential]
* Small change, present in quantal/raring and upstream.

** Affects: apt-cacher-ng (Ubuntu)
     Importance: High
         Status: Fix Released

** Affects: apt-cacher-ng (Ubuntu Precise)
     Importance: High
     Assignee: Chris J Arges (arges)
         Status: In Progress


** Tags: patch
-- 
High CPU usage on broken request to apt-cacher-ng
https://bugs.launchpad.net/bugs/999915
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