gpu: nvgpu: Do not access NULL pointer dev

In gk20a_busy() we check if dev is NULL and return -ENODEV if so. But
before that we've already dereferenced dev by passing it to
get_gk20a(). Defer call to get_gk20a() until after the NULL check.

Bug 200192125

Change-Id: I943a9e96d13ff8cb4333fe20a941c8e95d159a66
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1280349
GVS: Gerrit_Virtual_Submit

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 246338d4..b1e90bd8 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -1,7 +1,7 @@
 /*
  * GK20A Graphics
  *
- * Copyright (c) 2011-2016, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2017, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -1791,12 +1791,13 @@ static int gk20a_can_busy(struct gk20a *g)
 int gk20a_busy(struct device *dev)
 {
         int ret = 0;
-        struct gk20a *g = get_gk20a(dev);
+        struct gk20a *g;
         struct gk20a_platform *platform;
 
         if (!dev)
                 return -ENODEV;
 
+        g = get_gk20a(dev);
         platform = gk20a_get_platform(dev);
 
         if (!g || !gk20a_can_busy(g))