[Bug 930839] Re: update-manager crashed with SIGABRT in __assert_fail_base(): Assertion !xcb_xlib_unknown_req_in_deq failed in dequeue_pending_request

[Bryce Harrington]

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?

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to update-manager in Ubuntu.
https://bugs.launchpad.net/bugs/930839

Title:
  update-manager crashed with SIGABRT in __assert_fail_base(): Assertion
  !xcb_xlib_unknown_req_in_deq failed in dequeue_pending_request

Status in “update-manager” package in Ubuntu:
  Confirmed

Bug description:
  hell i dont know what is going on any more.

  <bdmurray> [xcb] Unknown sequence number while processing queue
  <bdmurray> [xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
  <bdmurray> [xcb] Aborting, sorry about that.
  <bdmurray> 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 i686
  ApportVersion: 1.91-0ubuntu1
  Architecture: i386
  Date: Sat Feb 11 21:33:21 2012
  ExecutablePath: /usr/bin/update-manager
  GsettingsChanges:

  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
  Signal: 6
  SourcePackage: update-manager
  StacktraceTop:
   raise () from /lib/i386-linux-gnu/libc.so.6
   abort () from /lib/i386-linux-gnu/libc.so.6
   ?? () from /lib/i386-linux-gnu/libc.so.6
   __assert_fail () from /lib/i386-linux-gnu/libc.so.6
   ?? () from /usr/lib/i386-linux-gnu/libX11.so.6
  Title: update-manager crashed with SIGABRT in raise()
  UpgradeStatus: Upgraded to precise on 2012-02-12 (0 days ago)
  UserGroups:

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/930839/+subscriptions