[PATCH 4.4 079/146] drm/nouveau: fix for disabled fbdev emulation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dmitrii Tcvetkov <demfloro@xxxxxxxxxxx>

commit 52dfcc5ccfbb6697ac3cac7f7ff1e712760e1216 upstream.

Hello,

after this commit:

commit f045f459d925138fe7d6193a8c86406bda7e49da
Author: Ben Skeggs <bskeggs@xxxxxxxxxx>
Date:   Thu Jun 2 12:23:31 2016 +1000
    drm/nouveau/fbcon: fix out-of-bounds memory accesses

kernel started to oops when loading nouveau module when using GTX 780 Ti
video adapter. This patch fixes the problem.

Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=120591

Signed-off-by: Dmitrii Tcvetkov <demfloro@xxxxxxxxxxx>
Suggested-by: Ilia Mirkin <imirkin@xxxxxxxxxxxx>
Fixes: f045f459d925 ("nouveau_fbcon_init()")
Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/nouveau/nouveau_fbcon.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -557,7 +557,8 @@ nouveau_fbcon_init(struct drm_device *de
 	if (ret)
 		goto fini;
 
-	fbcon->helper.fbdev->pixmap.buf_align = 4;
+	if (fbcon->helper.fbdev)
+		fbcon->helper.fbdev->pixmap.buf_align = 4;
 	return 0;
 
 fini: