Ubuntu
kde4libs package

[Maverick] drkonqi can't retrace crashes anymore

Bug #589841 reported by Philip Muškovac
28
This bug affects 4 people
Affects Status Importance Assigned to Milestone
kdelibs
Fix Released
Medium
kde4libs (Ubuntu)
Fix Released
High
Kees Cook
Ubuntu maverick-alpha-3
linux (Ubuntu)
Fix Released
High
Kees Cook
Ubuntu maverick-alpha-3

Bug Description

Binary package hint: kdebase-runtime

Trying to retrace a crash in drkonqi fails always and .xsession-errors shows:

ptrace: Operation not permitted.
/tmp/kde-yofel/drkonqiX21049.tmp:2: Error in sourced command file:
No thread selected

WORKAROUND:
run

echo 0 | sudo tee /proc/sys/kernel/ptrace_scope

in a terminal before pressing the 'Reload' button in DrKonqi. (And you should reset it to 1 again after you're finished retracing the crash)

ProblemType: BugDistroRelease: Ubuntu 10.10
Package: kdebase-runtime 4:4.4.80-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.34-5.13-generic 2.6.34
Uname: Linux 2.6.34-5-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Fri Jun 4 21:24:43 2010InstallationMedia: Kubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100427.1)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bashSourcePackage: kdebase-runtime

See original description
Revision history for this message
Philip Muškovac (yofel) wrote :
summary: - [Maverick] drkonq can't retrace crashes anymore
+ [Maverick] drkonqi can't retrace crashes anymore
Revision history for this message
Scott Kitterman (kitterman) wrote :

Feature, not a bug:

https://wiki.ubuntu.com/SecurityTeam/Roadmap/KernelHardening#PTRACE Protection

Revision history for this message
Kees Cook (kees) wrote :

Shouldn't apport be catching crashes? Why is it trying to ptrace? Normally retracing happens through a core file.

Revision history for this message
Scott Kitterman (kitterman) wrote :

We don't use apport for KDE packages. We use the KDE bug tool so reports can go directly upstream where (per our bug reporting policy for Kubuntu) they belong.

Changed in kdebase-runtime (Ubuntu):
status: New → Confirmed
importance: Undecided → High
Revision history for this message
Kees Cook (kees) wrote :

Hm, looks like kdeinit spawns the retracer. I'll think about how to handle this.

Changed in kdebase-runtime (Ubuntu):
assignee: nobody → Kees Cook (kees)
importance: High → Medium
Kees Cook (kees)
Changed in kdebase-runtime (Ubuntu):
assignee: Kees Cook (kees) → nobody
Revision history for this message
Jonathan Thomas (echidnaman) wrote :

Bumping to high; this renders Dr. Konqi useless.

Changed in kdebase-runtime (Ubuntu):
importance: Medium → High
Revision history for this message
Kees Cook (kees) wrote :

For Dr Konqi to operate as it is currently designed, the /proc/sys/kernel/ptrace_scope sysctl needs to be set to 0. Since the KDE crash handler is disabled at stable release, this is only a problem during the devel cycle. I would recommend that apport be used in favor of dr konqi, since it operates on core files rather than needing the process in memory.

Revision history for this message
Jonathan Thomas (echidnaman) wrote :

Disabling Dr. Konqi's not something that has been done in the past. Not that it wouldn't be a good idea...
But apport is very unstable due to bindings issues, and does not fall in line with the Kubuntu bug policy.

Revision history for this message
Jonathan Thomas (echidnaman) wrote :

Dr. Konqi is also an indispensable development tool. Having to run gdb all the time while developing an application is not very convenient at all, and Dr. Konqi allows the developer to run his program normally, and catch any random crash that may occur. While apport could in theory do this, the apport GUIs close before you get to a backtrace due to package un-officialness, and manually obtaining a backtrace with apport-retrace is slow black-magic.

I am sure we will lose many KDE developers who use Kubuntu on their development systems, and these developers tend to be the most vocal users, as well as users who have the greatest pedestal to dole out abuse/praise. A broken Dr. Konqi for Kubuntu 10.10 is unacceptable.

Revision history for this message
Philip Muškovac (yofel) wrote :

I put the way to get ptrace to work again into the description. Maybe we could make Drkonq check what the current setting is and allow it to change it to run ptrace? I personally wouldn't mind if that would require sudo rights.

description: updated
Revision history for this message
Jonathan Thomas (echidnaman) wrote :

If we used policykit, we could even ship a policy file so that it could be done without asking for a password at all. If nothing else gets done, I will go this route. (Using policykit to run that command on dr konqi start, and then un-echo it on close)

Kees Cook (kees)
affects: kdebase-runtime (Ubuntu) → kde4libs (Ubuntu)
Kees Cook (kees)
Changed in kde4libs (Ubuntu):
status: Confirmed → In Progress
milestone: none → maverick-alpha-3
assignee: nobody → Kees Cook (kees)
Changed in linux (Ubuntu):
assignee: nobody → Kees Cook (kees)
status: New → In Progress
milestone: none → maverick-alpha-3
importance: Undecided → High
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package kde4libs - 4:4.4.90-0ubuntu3

---------------
kde4libs (4:4.4.90-0ubuntu3) maverick; urgency=low

  * kubuntu_69_declare_debugger_pid.diff: delcare debugger PTRACE
    relationship (LP: #589841).
 -- Kees Cook <email address hidden> Thu, 01 Jul 2010 09:46:16 -0700

Changed in kde4libs (Ubuntu):
status: In Progress → Fix Released
Revision history for this message
Alessandro Ghersi (alessandro-ghersi) wrote :

Can you run "bzr add" and push again to bzr? The patch is missing:
http://bazaar.launchpad.net/~kubuntu-members/kdelibs/ubuntu/revision/244

Revision history for this message
Kees Cook (kees) wrote : Re: [Bug 589841] Re: [Maverick] drkonqi can't retrace crashes anymore

On Wed, Jul 07, 2010 at 12:24:20AM -0000, Alessandro Ghersi wrote:
> Can you run "bzr add" and push again to bzr? The patch is missing:
> http://bazaar.launchpad.net/~kubuntu-members/kdelibs/ubuntu/revision/244

Argh, thanks. I've re-pushed with the patch now.

Revision history for this message
Kees Cook (kees) wrote :

Once the -7 kernel publishes, this should all Just Work again. :)

Revision history for this message
Jonathan Thomas (echidnaman) wrote :

Thanks a lot!

Kees Cook (kees)
Changed in linux (Ubuntu):
status: In Progress → Fix Released
Bug Watch Updater (bug-watch-updater)
Changed in kdelibs:
status: Unknown → Fix Released
Bug Watch Updater (bug-watch-updater)
Changed in kdelibs:
importance: Unknown → Medium
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