Ubuntu
pygobject package

Crashes with GLib.child_watch_add

Bug #1078297 reported by Daniel Narvaez
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
pygobject (Ubuntu)
Fix Released
Undecided
Unassigned
Quantal
Fix Released
Undecided
Martin Pitt
Raring
Fix Released
Undecided
Unassigned

Bug Description

In a complex application, I'm seeing crashes when the destroy notify of GLib.child_watch_add is called.

#0 0x00000000004b5c78 in tupledealloc.24592 (op=0x316dc80)
        at ../Objects/tupleobject.c:218
    #1 0x00002b7c1553abc7 in child_watch_dnotify (data=0x345a320)
        at /build/buildd/pygobject-3.4.0/gi/_glib/glibmodule.c:355
    #2 0x00002b7c1409c108 in g_source_callback_unref (cb_data=0x3475f40)
        at /build/buildd/glib2.0-2.34.0/./glib/gmain.c:1457
    #3 g_source_callback_unref (cb_data=0x3475f40)
        at /build/buildd/glib2.0-2.34.0/./glib/gmain.c:1449
    #4 0x00002b7c1409c70a in g_source_destroy_internal (source=source@entry=
        0x3471370, context=context@entry=0x1d08a30, have_lock=have_lock@entry=1)
        at /build/buildd/glib2.0-2.34.0/./glib/gmain.c:1123
    #5 0x00002b7c1409eb00 in g_main_dispatch (context=0x1d08a30)
        at /build/buildd/glib2.0-2.34.0/./glib/gmain.c:2739

The problem has been fixed upstream

http://git.gnome.org/browse/pygobject/commit/?h=pygobject-3-4&id=a06e0d021d74c95cd517abb3e6ef5ff0037de679

REGRESSION POTENTIAL: Very low. This just adds locking around the reference handling to avoid race conditions with concurrent access. pyglib_gil_state_{ensure,release}() is used all over the place in pygobject, but it was forgotten in this particular function.

SRU TEST CASE: This is rather hard to reproduce, as it is a race condition in a multi-threaded program. As Daniel can reproduce it rather well, I suggest to ask him to verify the SRU.

See also bug 1083694 which is the same hang for software-center; this also has a test case.

See original description
Revision history for this message
Daniel Narvaez (dwnarvaez) wrote :

Forgot to mention this happens with Ubuntu 12.10, both 32 and 64 bit. Package version is 3.4.0-1

Revision history for this message
Martin Pitt (pitti) wrote :

This was fixed in raring in 3.4.2-1.

Changed in pygobject (Ubuntu Raring):
status: New → Fix Released
Revision history for this message
Martin Pitt (pitti) wrote :

I uploaded the fix for Quantal to the -proposed queue for SRU team review.

Changed in pygobject (Ubuntu Quantal):
status: New → In Progress
description: updated
Martin Pitt (pitti)
Changed in pygobject (Ubuntu Quantal):
assignee: nobody → Martin Pitt (pitti)
Martin Pitt (pitti)
description: updated
Martin Pitt (pitti)
description: updated
Revision history for this message
Brian Murray (brian-murray) wrote : Please test proposed package

Hello Daniel, or anyone else affected,

Accepted pygobject into quantal-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/pygobject/3.4.0-1ubuntu0.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please change the bug tag from verification-needed to verification-done. If it does not, change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Changed in pygobject (Ubuntu Quantal):
status: In Progress → Fix Committed
tags: added: verification-needed
Daniel Narvaez (dwnarvaez)
tags: added: verification-done
removed: verification-needed
Revision history for this message
Colin Watson (cjwatson) wrote : Update Released

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package pygobject - 3.4.0-1ubuntu0.1

---------------
pygobject (3.4.0-1ubuntu0.1) quantal-proposed; urgency=low

  * Add 00git_lock_gil_in_child_watch_add.patch: Fix crash with
    GLib.child_watch_add() by locking the Python interpreter, to avoid race
    conditions in multi-threaded programs. (LP: #1078297)
 -- Martin Pitt <email address hidden> Tue, 13 Nov 2012 16:18:17 +0100

Changed in pygobject (Ubuntu Quantal):
status: Fix Committed → Fix Released
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