In gtk draw/render callbacks, add an early NULL check for the console
surface and skip drawing if it's NULL. Otherwise, attempting to fetch
its width and height crash. This change fixes Coverity CID 1610328.

In practice, this case wouldn't happen at all because we always install
a placeholder surface to the console when there is nothing to display.

Resolves: Coverity CID 1610328
Signed-off-by: Weifeng Liu <weifeng.liu.z@gmail.com>
---
 ui/gtk-egl.c     | 5 +----
 ui/gtk-gl-area.c | 5 +----
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index 0b787bea25..ae9239999c 100644
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -72,7 +72,7 @@ void gd_egl_draw(VirtualConsole *vc)
 #endif
     int ww, wh, pw, ph, gs;
 
-    if (!vc->gfx.gls) {
+    if (!vc->gfx.gls || !vc->gfx.ds) {
         return;
     }
 
@@ -112,9 +112,6 @@ void gd_egl_draw(VirtualConsole *vc)
         }
 #endif
     } else {
-        if (!vc->gfx.ds) {
-            return;
-        }
         eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
                        vc->gfx.esurface, vc->gfx.ectx);
 
diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
index 8151cc413c..05fc38096e 100644
--- a/ui/gtk-gl-area.c
+++ b/ui/gtk-gl-area.c
@@ -48,7 +48,7 @@ void gd_gl_area_draw(VirtualConsole *vc)
     int fbw, fbh;
     int wx_offset, wy_offset;
 
-    if (!vc->gfx.gls) {
+    if (!vc->gfx.gls || !vc->gfx.ds) {
         return;
     }
 
@@ -135,9 +135,6 @@ void gd_gl_area_draw(VirtualConsole *vc)
         }
 #endif
     } else {
-        if (!vc->gfx.ds) {
-            return;
-        }
         gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
 
         surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, pw, ph);
-- 
2.49.0

On 2025/07/14 23:17, Weifeng Liu wrote:
> In gtk draw/render callbacks, add an early NULL check for the console
> surface and skip drawing if it's NULL. Otherwise, attempting to fetch
> its width and height crash. This change fixes Coverity CID 1610328.
> 
> In practice, this case wouldn't happen at all because we always install
> a placeholder surface to the console when there is nothing to display.
> 
> Resolves: Coverity CID 1610328
> Signed-off-by: Weifeng Liu <weifeng.liu.z@gmail.com>

Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>

On Mon, Jul 14, 2025 at 6:18 PM Weifeng Liu <weifeng.liu.z@gmail.com> wrote:
>
> In gtk draw/render callbacks, add an early NULL check for the console
> surface and skip drawing if it's NULL. Otherwise, attempting to fetch
> its width and height crash. This change fixes Coverity CID 1610328.
>
> In practice, this case wouldn't happen at all because we always install
> a placeholder surface to the console when there is nothing to display.
>
> Resolves: Coverity CID 1610328
> Signed-off-by: Weifeng Liu <weifeng.liu.z@gmail.com>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  ui/gtk-egl.c     | 5 +----
>  ui/gtk-gl-area.c | 5 +----
>  2 files changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
> index 0b787bea25..ae9239999c 100644
> --- a/ui/gtk-egl.c
> +++ b/ui/gtk-egl.c
> @@ -72,7 +72,7 @@ void gd_egl_draw(VirtualConsole *vc)
>  #endif
>      int ww, wh, pw, ph, gs;
>
> -    if (!vc->gfx.gls) {
> +    if (!vc->gfx.gls || !vc->gfx.ds) {
>          return;
>      }
>
> @@ -112,9 +112,6 @@ void gd_egl_draw(VirtualConsole *vc)
>          }
>  #endif
>      } else {
> -        if (!vc->gfx.ds) {
> -            return;
> -        }
>          eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
>                         vc->gfx.esurface, vc->gfx.ectx);
>
> diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
> index 8151cc413c..05fc38096e 100644
> --- a/ui/gtk-gl-area.c
> +++ b/ui/gtk-gl-area.c
> @@ -48,7 +48,7 @@ void gd_gl_area_draw(VirtualConsole *vc)
>      int fbw, fbh;
>      int wx_offset, wy_offset;
>
> -    if (!vc->gfx.gls) {
> +    if (!vc->gfx.gls || !vc->gfx.ds) {
>          return;
>      }
>
> @@ -135,9 +135,6 @@ void gd_gl_area_draw(VirtualConsole *vc)
>          }
>  #endif
>      } else {
> -        if (!vc->gfx.ds) {
> -            return;
> -        }
>          gtk_gl_area_make_current(GTK_GL_AREA(vc->gfx.drawing_area));
>
>          surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, pw, ph);
> --
> 2.49.0
>


-- 
Marc-André Lureau