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From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 01 Jun 2016 08:38:17 +0200
In-Reply-To: <2e555d67b7e53a86bef98f774a2706f2b0ec4ea0.1464728215.git.crobinso@redhat.com>
References: <2e555d67b7e53a86bef98f774a2706f2b0ec4ea0.1464728215.git.crobinso@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] ui: sdl2: Fix crash with -nodefaults -sdl
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To: Cole Robinson <crobinso@redhat.com>
Cc: qemu-devel@nongnu.org

On Di, 2016-05-31 at 16:56 -0400, Cole Robinson wrote:
> $ ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -sdl
> Segmentation fault (core dumped)
>=20
> 0  0x00005555559631af in sdl_display_init (ds=3D<optimized out>, full_scr=
een=3D0, no_frame=3D<optimized out>) at ui/sdl2.c:822
> 1  0x00005555556c8a9a in main (argc=3D<optimized out>, argv=3D<optimized =
out>, envp=3D<optimized out>) at vl.c:4527
>=20
> Setting the window icon assumes there's always an SDL output window
> available, which isn't the case with when there's no video device,
> like via -nodefaults. So don't try to set a window icon when we don't
> have any outputs.

Hmm, I guess we can skip pretty much all of the init in case there are
no outputs:

@@ -794,6 +794,9 @@ void sdl_display_init(DisplayState *ds, int
full_screen, int no_frame)
         }
     }
     sdl2_num_outputs =3D i;
+    if (sdl2_num_outputs =3D=3D 0) {
+        return;
+    }
     sdl2_console =3D g_new0(struct sdl2_console, sdl2_num_outputs);
     for (i =3D 0; i < sdl2_num_outputs; i++) {
         QemuConsole *con =3D qemu_console_lookup_by_index(i);


Maybe even move up the loop counting the outputs, so we can skip the
SDL_Init() call too.  We don't get a empty window then.

cheers,
  Gerd