[PATCH] fb: reject enable request when framebuffer has no mode

[Lucas Stach]

If no display is connected or the display modes are incompatible with
the scanout hardware we might end up with a registered framebuffer with
no modes. Trying to enable such a framebuffer will blow up with NULL
ptr dereferences in various places, so just don't do it.

Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
---
 drivers/video/fb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/video/fb.c b/drivers/video/fb.c
index 004df1e604d6..599ac5b75e0a 100644
--- a/drivers/video/fb.c
+++ b/drivers/video/fb.c
@@ -124,6 +124,9 @@ static int fb_enable_set(struct param_d *param, void *priv)
 	struct fb_info *info = priv;
 	int enable;
 
+	if (!info->mode)
+		return -EINVAL;
+
 	enable = info->p_enable;
 
 	if (enable)
-- 
2.16.1