usb backend dies with segfault

[Stefan K.]

Binary package hint: cups

This bug is probably related to #461020 and #564917. One is already "fix released" (don't want to disturb here) and the other one is pretty old and affects karmic. So I decided to file another report for lucid. Sorry, if my assumption is wrong.

What I expected: It works :)

What happened instead: Well, I have a Parallel-To-USB adapter cable for my ancient "NEC Pinwriter P60" and hooked up another printer directly to USB (Kyocera Laser Printer). The usb backend of cups is running fine as long the adapter is not connected. Once it is plugged in and I manually run "/usr/lib/cups/backend/usb" in a terminal to scan for usb devices, it dies with a segfault in libc6. CUPS says "backend failed" accordingly. Unfortunately this also disables the laser printer as this runs on that backend too.

Maybe I shall try using the parallel backend on the NEC. I didn't do this so far because the machine is in my office. And currently I am writing from home testing that cable. This workaround may work with that adapter or not but won't help against the segfault.

I attached a crash report from apport and a core dump. Both machines run lucid 10.04.2. Additionally I tested it with Live-CDs booted by grub on my home machine. Karmic, Lucid and Maverick are affected. Natty (Alpha-3) is not. The usb backend does work here with the adapter.

OS release: Description: Ubuntu 10.04.2 LTS Release: 10.04
Kernel: Linux sohn 2.6.32-30-generic #59-Ubuntu SMP Tue Mar 1 21:30:46 UTC 2011 x86_64 GNU/Linux

CUPS versions
karmic 1.4.1-5ubuntu2
lucid 1.4.3-1ubuntu1.3
maverick 1.4.4-6ubuntu2
natty 1.4.6-3

(eg)libc6 versions
karmic 2.10.1-0ubuntu15
lucid 2.11.1-0ubuntu7.8
maverick 2.12.1-ubuntu6
natty 2.13-0ubuntu7 (maybe a bit older in alpha3)

[Till Kamppeter (till-kamppeter)]

I have checked debian/changelog of CUPS and found out that I introduced the fix for your problem as fix for bug 564917 on Jan 4, 2011. This fits perfectly to the fact that the first Ubuntu release without the bug is Natty, as you have found out. This confirms for the first time that my fix actually works (on bug 564917 I did not get any appropriate answer from the users) and also that this bug is a duplicate of bug 564917. Therefore I have marked it as such.

The current problem is more that the bug still exists in older releases, especially Maverick and Lucid. Perhaps one should consider the fix for an SRU (Stable Release Update).

[Till Kamppeter (till-kamppeter)]

Thank you anyway for your new bug report, especially for confirming that Natty is the first Ubuntu release with the problem fixed.