staging: drm/omap: Validate debugfs device

Added check for valid device information before dumping debugfs
information.

Signed-off-by: Andy Gross <andy.gross@ti.com>
Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/staging/omapdrm/omap_dmm_tiler.c b/drivers/staging/omapdrm/omap_dmm_tiler.c
index 852d9440f72..e4c7bb6afce 100644
--- a/drivers/staging/omapdrm/omap_dmm_tiler.c
+++ b/drivers/staging/omapdrm/omap_dmm_tiler.c
@@ -766,10 +766,18 @@ int tiler_map_show(struct seq_file *s, void *arg)
         const char *a2d = special;
         const char *m2dp = m2d, *a2dp = a2d;
         char nice[128];
-        int h_adj = omap_dmm->lut_height / ydiv;
-        int w_adj = omap_dmm->lut_width / xdiv;
+        int h_adj;
+        int w_adj;
         unsigned long flags;
 
+        if (!omap_dmm) {
+                /* early return if dmm/tiler device is not initialized */
+                return 0;
+        }
+
+        h_adj = omap_dmm->lut_height / ydiv;
+        w_adj = omap_dmm->lut_width / xdiv;
+
         map = kzalloc(h_adj * sizeof(*map), GFP_KERNEL);
         global_map = kzalloc((w_adj + 1) * h_adj, GFP_KERNEL);