The error message "Unknown sequence number while processing queue" occurs in a chunk of text that has this big fat warning in front of it, about threading safety in client code:
/* Thread-safety rules: * * At most one thread can be reading from XCB's event queue at a time. * If you are not the current event-reading thread and you need to find * out if an event is available, you must wait. * * The same rule applies for reading replies. * * A single thread cannot be both the the event-reading and the * reply-reading thread at the same time. * * We always look at both the current event and the first pending reply * to decide which to process next. * * We always process all responses in sequence-number order, which may * mean waiting for another thread (either the event_waiter or the * reply_waiter) to handle an earlier response before we can process or * return a later one. If so, we wait on the corresponding condition * variable for that thread to process the response and wake us up. */ This seems to suggest perhaps this client application could have some faulty logic in its thread handling as relating to the xcb calls? ** Description changed: Occurred when updating. + + [xcb] Unknown sequence number while processing queue + [xcb] Most likely this is a multi-threaded client and XInitThreads has not been called + [xcb] Aborting, sorry about that. + python: ../../src/xcb_io.c:273: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed. ProblemType: Crash DistroRelease: Ubuntu 12.04 Package: update-manager 1:0.156.4 ProcVersionSignature: Ubuntu 3.2.0-15.24-generic 3.2.5 Uname: Linux 3.2.0-15-generic x86_64 ApportVersion: 1.91-0ubuntu1 Architecture: amd64 AssertionMessage: python: ../../src/xcb_io.c:273: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed. Date: Thu Feb 9 23:36:59 2012 DuplicateOf: https://bugs.launchpad.net/bugs/926238 ExecutablePath: /usr/bin/update-manager GsettingsChanges: - com.ubuntu.update-manager first-run false - com.ubuntu.update-manager launch-time 1327193820 - com.ubuntu.update-manager show-details true - com.ubuntu.update-manager window-height 600 - com.ubuntu.update-manager window-width 600 + com.ubuntu.update-manager first-run false + com.ubuntu.update-manager launch-time 1327193820 + com.ubuntu.update-manager show-details true + com.ubuntu.update-manager window-height 600 + com.ubuntu.update-manager window-width 600 InterpreterPath: /usr/bin/python2.7 PackageArchitecture: all ProcCmdline: /usr/bin/python /usr/bin/update-manager --dist-upgrade ProcEnviron: - PATH=(custom, no user) - LANG=en_US.UTF-8 - SHELL=/bin/bash + PATH=(custom, no user) + LANG=en_US.UTF-8 + SHELL=/bin/bash Signal: 6 SourcePackage: update-manager StacktraceTop: - __assert_fail_base (fmt=<optimized out>, assertion=0x7f20d7ceead8 "!xcb_xlib_threads_sequence_lost", file=0x7f20d7ceed92 "../../src/xcb_io.c", line=<optimized out>, function=<optimized out>) at assert.c:94 - __GI___assert_fail (assertion=0x7f20d7ceead8 "!xcb_xlib_threads_sequence_lost", file=0x7f20d7ceed92 "../../src/xcb_io.c", line=273, function=0x7f20d7ceeeb8 "poll_for_event") at assert.c:103 - ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6 - ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6 - _XEventsQueued () from /usr/lib/x86_64-linux-gnu/libX11.so.6 + __assert_fail_base (fmt=<optimized out>, assertion=0x7f20d7ceead8 "!xcb_xlib_threads_sequence_lost", file=0x7f20d7ceed92 "../../src/xcb_io.c", line=<optimized out>, function=<optimized out>) at assert.c:94 + __GI___assert_fail (assertion=0x7f20d7ceead8 "!xcb_xlib_threads_sequence_lost", file=0x7f20d7ceed92 "../../src/xcb_io.c", line=273, function=0x7f20d7ceeeb8 "poll_for_event") at assert.c:103 + ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6 + ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6 + _XEventsQueued () from /usr/lib/x86_64-linux-gnu/libX11.so.6 Title: update-manager assert failure: python: ../../src/xcb_io.c:273: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed. UpgradeStatus: Upgraded to precise on 2012-02-10 (0 days ago) UserGroups: -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/930004 Title: update-manager assert failure: python: ../../src/xcb_io.c:273: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/930004/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
