widget: fix invalid memory ref after channel is distroyed

When the display channel is destroyed, we disconnect all signals
handlers, but we don't remove the reference on the primary surface
data, and that can lead to crashes in a later expose event, reusing
the canvas surface (ex, if scaling is disabled). Call
primary_destroy() when disconnecting the channel from the widget.

We now keep the primary surface during channel reset (right after
disconnect for example), so the primary surface can be eventually
recycled, and the widget still holds a valid reference until the
signal is received. The primary surface is ultimately destroyed during
finalize, or if the new primary surface size doesn't match.

Program received signal SIGSEGV, Segmentation fault.
__memmove_ssse3_back () at ../sysdeps/x86_64/multiarch/memcpy-ssse3-back.S:2130
2130		lddqu	-68(%rsi), %xmm0
Missing separate debuginfos, use: debuginfo-install gtk2-engines-2.20.2-2.fc15.x86_64 libusb1-1.0.9-0.3.rc1.fc16.x86_64 p11-kit-0.6-1.fc16.x86_64
(gdb) bt
    at ../sysdeps/x86_64/multiarch/memcpy-ssse3-back.S:2130
    srclen=<optimized out>, srcinc=4096, destinc=68, height=<optimized out>,
    half_order=0) at /usr/include/bits/string3.h:52
    dest_bits_per_pixel=32, req_yoffset=<optimized out>, req_xoffset=0,
    image=0x7fffffffb9a0, req=<optimized out>, dpy=0x64a630) at PutImage.c:821
    req_height=<optimized out>, req_width=<optimized out>, y=<optimized out>,
    x=0, req_yoffset=<optimized out>, req_xoffset=0, image=0x7fffffffb9a0,
    gc=0xa817e0, d=33554452, dpy=0x64a630) at PutImage.c:870
    req_xoffset=0, req_yoffset=<optimized out>, x=0, y=26, req_width=17,
    req_height=20, dest_bits_per_pixel=32, dest_scanline_pad=32)
    at PutImage.c:908
    image=0x7fffffffb9a0, req_xoffset=0, req_yoffset=0, x=0, y=26,
    req_width=17, req_height=20) at PutImage.c:1027
    image=<optimized out>, src_x=0, src_y=0, width=17, height=20, dst_x=0,
    dst_y=26) at cairo-xlib-surface.c:1357
---Type <return> to continue, or q <return> to quit---c
    height=20, width=17, dst_y=26, dst_x=0, src_y=<optimized out>,
    src_x=<optimized out>, pattern=0x7fffffffc6b0, op=CAIRO_OPERATOR_OVER,
    surface=0xb9a650) at cairo-xlib-surface.c:2403
    dst_y=26, dst_x=0, mask_y=0, mask_x=0, src_y=26, src_x=0,
    abstract_dst=0xb9a650, mask_pattern=0x0, src_pattern=0x7fffffffc6b0,
    op=CAIRO_OPERATOR_OVER) at cairo-xlib-surface.c:2452
    src_pattern=0x7fffffffc6b0, mask_pattern=0x0, abstract_dst=0xb9a650,
    src_x=0, src_y=26, mask_x=0, mask_y=0, dst_x=0, dst_y=26, width=17,
    height=20, clip_region=0x0) at cairo-xlib-surface.c:2415
    src=0x7fffffffc6b0, mask=0x0, dst=0xb9a650, src_x=0, src_y=26, mask_x=0,
    mask_y=0, dst_x=0, dst_y=26, width=17, height=20, clip_region=0x0)
    at cairo-surface.c:1802
    traps=0x7fffffffbee0, src=0x7fffffffc6b0, op=CAIRO_OPERATOR_OVER,
    dst=0xb9a650) at cairo-surface-fallback.c:762
    op=CAIRO_OPERATOR_OVER, dst=0xb9a650, traps=0x7fffffffbee0,
    antialias=CAIRO_ANTIALIAS_DEFAULT, clip=0x0, extents=0x7fffffffc600)
    at cairo-surface-fallback.c:812
---Type <return> to continue, or q <return> to quit---bt
    op=CAIRO_OPERATOR_OVER, source=0x7fffffffc6b0, clip=0x0)
    at cairo-surface-fallback.c:935
    source=0x7fffffffc6b0, op=CAIRO_OPERATOR_OVER, surface=0xb9a650)
    at cairo-surface.c:2027
    source=0x7fffffffc6b0, clip=0x7fffffffc7b0) at cairo-surface.c:1993
    at cairo-gstate.c:1049
    at spice-widget-cairo.c:104
    expose=0x7fffffffceb0) at spice-widget-cairo.c:133
    expose=0x7fffffffceb0) at spice-widget.c:885
    return_value=0x7fffffffca60, n_param_values=<optimized out>,
    param_values=0x7fffffffcad0, invocation_hint=<optimized out>,
    marshal_data=<optimized out>) at gtkmarshalers.c:86
    return_value=0x7fffffffca60, n_param_values=2,
    param_values=0x7fffffffcad0, invocation_hint=<optimized out>)
---Type <return> to continue, or q <return> to quit---c
    at gclosure.c:777
    detail=0, instance=<optimized out>, emission_return=0x7fffffffccb0,
    instance_and_params=0x7fffffffcad0) at gsignal.c:3584
    signal_id=<optimized out>, detail=0, var_args=<optimized out>)
    at gsignal.c:3305
    signal_id=<optimized out>, detail=<optimized out>) at gsignal.c:3351
    event=0x7fffffffceb0) at gtkwidget.c:4999

1 files changed, 1 insertions, 0 deletions

diff --git a/gtk/spice-widget.c b/gtk/spice-widget.c
index db53928..c13f758 100644
--- a/gtk/spice-widget.c
+++ b/gtk/spice-widget.c
@@ -1740,6 +1740,7 @@ static void disconnect_display(SpiceDisplay *display)
                                          display);
     g_signal_handlers_disconnect_by_func(d->display, G_CALLBACK(invalidate),
                                          display);
+    primary_destroy(d->display, display);
     d->display = NULL;
 }