[PATCH -next] drm/i915: fix potential NULL pointer dereference in i915_gem_context_get_hang_stats()

From: Wei Yongjun
Date: Wed Jun 19 2013 - 20:01:54 EST


From: Wei Yongjun <yongjun_wei@xxxxxxxxxxxxxxxxx>

The dereference should be moved below the NULL test.

Signed-off-by: Wei Yongjun <yongjun_wei@xxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_context.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index ff47145..f32107e 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -309,7 +309,7 @@ i915_gem_context_get_hang_stats(struct intel_ring_buffer *ring,
u32 id)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
- struct drm_i915_file_private *file_priv = file->driver_priv;
+ struct drm_i915_file_private *file_priv;
struct i915_hw_context *to;

if (dev_priv->hw_contexts_disabled)
@@ -321,6 +321,7 @@ i915_gem_context_get_hang_stats(struct intel_ring_buffer *ring,
if (file == NULL)
return ERR_PTR(-EINVAL);

+ file_priv = file->driver_priv;
if (id == DEFAULT_CONTEXT_ID)
return &file_priv->hang_stats;


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