[Xcb] xcb 1.1 dead lock

Barton C Massey bart at cs.pdx.edu
Sat Dec 22 15:24:54 PST 2007


In message <1198358113.17587.25.camel at avenin.ebourne.me.uk> you wrote:
> It looks like I'm also getting this deadlock, with current ekiga svn. I
> was originally getting this deadlock:
> http://mail.gnome.org/archives/ekiga-devel-list/2007-December/msg00030.html
> which seems to have been fixed by this:
> http://lists.freedesktop.org/archives/xcb-commit/2007-October/000546.html
> 
> Now I have the backtrace below where XTranslateCoordinates seems to be
> the issue. Any suggestions on how to nail this one?

Thanks hugely for the stack backtrace!

It looks like threads 2 and 1 are both blocked in _XReply
waiting for a TranslateCoordinates response.  Are you sure
that this is the source of the deadlock?  There seem to be a
number of blocked threads.

Are you sure that ekiga is locking and unlocking a threaded
version of Xlib correctly?  I would expect this behavior if
ekiga failed to call XLockDisplay() and XUnlockDisplay()
around XTranslateCoordinates() calls, or if XInitThreads()
returned false.

Then again, I would also have expected XCB to do the right
thing even without the explicit locking.  So what do I know?

Maybe Jamey will spot something I've missed.

    Bart


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