Red Hat Bugzilla – Bug 427810
libxcb deadlocks and ioerrors
Last modified: 2009-07-14 10:58:34 EDT
Description of problem: multi threaded applications using a listener thread deadlock in libxcb Version-Release number of selected component (if applicable): libxcb-1.0.4 and forward How reproducible: Try to start cinelerra, nearly every thread set deadlocks Steps to Reproduce: 1. access cinelerra 1.2, compile, and run Actual results: several deadlocks, XNextEvent listener threads receive replies for XTranslateCoordinates, but XNextEvent thread holds c->xlib.lock and is not c->xlib.thread and so is locked by pthread_cond_wait(&c->xlib.cond, &c->iolock), since reply thread cant access lock program hangs. Expected results: No deadlocks delivering reply Additional info: The loop that enforces current thread as requester is not needed. The principle reason for the reply/event queues seem to be so that this operation is not required. Additionally, when an error reply is returned, read_packet errantly updates c->in.request_completed, causing poll_for_reply to later return a null reply (if(request == c->in.request_completed)). This returns a few levels and causes _XReply to report an errant IOError. It is not clear what the calling thread should return from the code when a listener thread intercepts an error reply. The patch was not well tested.
Created attachment 290986 [details] deadlocks/ioerrors patch
Changing version to '9' as part of upcoming Fedora 9 GA. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
This message is a reminder that Fedora 9 is nearing its end of life. Approximately 30 (thirty) days from now Fedora will stop maintaining and issuing updates for Fedora 9. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as WONTFIX if it remains open with a Fedora 'version' of '9'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version prior to Fedora 9's end of life. Bug Reporter: Thank you for reporting this issue and we are sorry that we may not be able to fix it before Fedora 9 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora please change the 'version' of this bug to the applicable version. If you are unable to change the version, please add a comment here and someone will do it for you. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete. The process we are following is described here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
Fedora 9 changed to end-of-life (EOL) status on 2009-07-10. Fedora 9 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. Thank you for reporting this bug and we are sorry it could not be fixed.