[Mesa-dev] [android-x86-devel] Re: need-help: how to change to newest mesa in android-x86?

[Dave Airlie]

>
> well, nothing specific, but for example early on we had some confusion
> in drm_gralloc (when adding dmabuf fd support) about who close()d the
> fd's.  Resulting in same fd getting closed twice (although some
> completely unrelated file handle might have snuck into that slot
> between the two close()s).
>
> Or you could end up w/ the same sort of thing for gem handles (which
> are unique to the drm device fd, so if you open() the device multiple
> times..).  I did initially have some confusion about this, w/ multiple
> fd_bo's (or pipe_resource's) being created for a given gem handle, and
> first one that gets deleted takes away the backing store that both
> userspace references where using.
>
> You might want to look at freedreno_drm_winsys.c and the crazy things
> it does..  I suspect virgl might need similar hacks.  That is really
> one part of two, that ensures that we share the same pipe_screen, and
> therefore (from libdrm) fd_device, for a given drm device fd.  The
> other part is that fd_device has hashtables to deal w/ double import
> of gem buffers.

I think Rob Clark might be on the right track here.

it sounds like the host is sending double deletes for some objects, which
sounds like a possible reference counting bug in the host.

So possibly something drm_gralloc, but it could be a bug in mesa, though
I haven't triggered anything like this yet.

I'd be more willing to look at this if/when there is an easy to
produce android-x86
image that I could just drop newer mesa/drm_gralloc into, I suppose I could look
at ARM images, but I'm not really setup for cross dev, and I've a few
other things to
be doing.

Dave.