[libvirt] Deadlock when using custom handlers

[Daniel P. Berrange]

On Tue, Aug 16, 2011 at 02:24:53PM +0200, Guido Günther wrote:
> Hi Daniel,
> On Sat, Aug 13, 2011 at 08:57:45PM -0700, Daniel P. Berrange wrote:
> > On Fri, Aug 12, 2011 at 11:54:28PM +0200, Guido Günther wrote:
> [..snip..] 
> > In the default libvirt event loop, the 'ff' callback is always invoked
> > from a "clean" stack in the event loop, so you never have this problem
> > with re-entrancy.
> > 
> > > Working around this by removing the locks from
> > > virNetSocketRemoveIOCallback leads to another deadlock:
> > 
> > Yeah this is not a viable approach. 
> Sure. This was only to see what else fails.
> 
> > > 
> > > I didn't see a simple way to fix this but would welcome any suggestions.
> > 
> > IMHO we just have to document that event loop implementations
> > should make sure that the 'ff' callbacks are always invoked
> > from a clean stack. In the case of virt-viewer, this means
> > changing it to register a g_idle  callback function to invoke
> > the 'ff' callback.
> 
> Patch for virt-viewer attached. I'll come up with a doc patch for
> libvirt once I have a bit more time.

Thanks, I have applied this patch.

Regards,
Daniel
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