Re: [gtk-vnc-devel] crash in coroutine

["Daniel P. Berrange" <berrange redhat com>]

On Thu, Jan 17, 2008 at 03:10:47PM -0300, Jonh Wendell wrote:
> Hi, guys.
> 
> There is a bug opened against vinagre, about a crash when a host is not
> found. The bug report is at: https://bugs.launchpad.net/bugs/183169
> 
> In Ubuntu Gutsy (where I am running now) it works fine. But on Hardy, or
> even in Foresight VMWare image (running GNOME 2.21 alpha) the bug is
> reproducible.

Ok, I think I understand why this happens. In the last bit of code in the
coroutine before it exits it does

        g_object_unref(G_OBJECT(obj));

In this case it is causing the vncdisplay widget to be destroyed & free'd.
This includes the co-routine state. Unfortunately, this co-routine state
is still needed in order to switch back to the main context.

Rather than unref'ing the object in vnc_coroutine cleeanup code, we need
to register a 'release' function when initially creating the coroutine
and unref it there instead. 

Oh, and we need to fix 'coroutine_swap/_coroutine_release so that they
don't access the 'struct coroutine' object after the 'release' callback
has been called.

The same problem will deinitely impact both ucontext & gthread coroutines.

Dan.
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