On 7/13/20 2:45 PM, Gerd Hoffmann wrote:
> Calling ramfb_display_update() might replace the DisplaySurface with the
> boot display, which in turn will free the currently active
> DisplaySurface.
>
> So clear our DisplaySurface pinter (dpy->region.surface pointer) to (a)
> avoid use-after-free and (b) force replacing the boot display with the
> real display when switching back.
>
> Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
> ---
> hw/vfio/display.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/vfio/display.c b/hw/vfio/display.c
> index a57a22674d62..342054193b3c 100644
> --- a/hw/vfio/display.c
> +++ b/hw/vfio/display.c
> @@ -405,6 +405,7 @@ static void vfio_display_region_update(void *opaque)
> if (!plane.drm_format || !plane.size) {
> if (dpy->ramfb) {
> ramfb_display_update(dpy->con, dpy->ramfb);
> + dpy->region.surface = NULL;
> }
> return;
> }
>
More generic fix:
-- >8 --
--- a/ui/console.c
+++ b/ui/console.c
@@ -1580,10 +1580,10 @@ void dpy_gfx_replace_surface(QemuConsole *con,
DisplaySurface *surface)
{
DisplayState *s = con->ds;
- DisplaySurface *old_surface = con->surface;
+ QemuConsole *old_con = con;
DisplayChangeListener *dcl;
- assert(old_surface != surface || surface == NULL);
+ assert(con->surface != surface || surface == NULL);
con->surface = surface;
QLIST_FOREACH(dcl, &s->listeners, next) {
@@ -1594,7 +1594,8 @@ void dpy_gfx_replace_surface(QemuConsole *con,
dcl->ops->dpy_gfx_switch(dcl, surface);
}
}
- qemu_free_displaysurface(old_surface);
+ qemu_free_displaysurface(old_con->surface);
+ old_con->surface = NULL;
}
---
