[PATCH] hw/display/omap_lcdc: Fix potential NULL pointer dereference

[AlexChen]

In omap_lcd_interrupts(), the pointer omap_lcd is dereferenced before
being check if it is valid, which may lead to NULL pointer dereference.
So move the assignment to surface after checking that the omap_lcd is valid.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Alex Chen <alex.chen@huawei.com>
---
 hw/display/omap_lcdc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/display/omap_lcdc.c b/hw/display/omap_lcdc.c
index fa4a381db6..2941c5c67c 100644
--- a/hw/display/omap_lcdc.c
+++ b/hw/display/omap_lcdc.c
@@ -78,7 +78,7 @@ static void omap_lcd_interrupts(struct omap_lcd_panel_s *s)
 static void omap_update_display(void *opaque)
 {
     struct omap_lcd_panel_s *omap_lcd = (struct omap_lcd_panel_s *) opaque;
-    DisplaySurface *surface = qemu_console_surface(omap_lcd->con);
+    DisplaySurface *surface;
     draw_line_func draw_line;
     int size, height, first, last;
     int width, linesize, step, bpp, frame_offset;
@@ -89,6 +89,7 @@ static void omap_update_display(void *opaque)
         return;
     }

+    surface = qemu_console_surface(omap_lcd->con);
     frame_offset = 0;
     if (omap_lcd->plm != 2) {
         cpu_physical_memory_read(
-- 
2.19.1