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

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

From: Chris Wilson <[email protected]>

commit 0d1430a3f4b7cfd8779b78740a4182321f3ca7f3 upstream.

Inorder to serialise the closing of the file descriptor and its
subsequent release of client requests with i915_gem_free_request(), we
need to hold the struct_mutex in i915_gem_release(). Failing to do so
has the potential to trigger an OOPS, later with a use-after-free.

Testcase: igt/gem_close_race
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70874
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71029
Reported-by: Eric Anholt <[email protected]>
Signed-off-by: Chris Wilson <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Signed-off-by: Luis Henriques <[email protected]>
---
 drivers/gpu/drm/i915/i915_dma.c         | 2 ++
 drivers/gpu/drm/i915/i915_gem_context.c | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index f466980..fc34376 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1831,8 +1831,10 @@ void i915_driver_lastclose(struct drm_device * dev)
 
 void i915_driver_preclose(struct drm_device * dev, struct drm_file *file_priv)
 {
+       mutex_lock(&dev->struct_mutex);
        i915_gem_context_close(dev, file_priv);
        i915_gem_release(dev, file_priv);
+       mutex_unlock(&dev->struct_mutex);
 }
 
 void i915_driver_postclose(struct drm_device *dev, struct drm_file *file)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c 
b/drivers/gpu/drm/i915/i915_gem_context.c
index 51b7a21..90b0491 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -335,10 +335,8 @@ void i915_gem_context_close(struct drm_device *dev, struct 
drm_file *file)
 {
        struct drm_i915_file_private *file_priv = file->driver_priv;
 
-       mutex_lock(&dev->struct_mutex);
        idr_for_each(&file_priv->context_idr, context_idr_cleanup, NULL);
        idr_destroy(&file_priv->context_idr);
-       mutex_unlock(&dev->struct_mutex);
 }
 
 static struct i915_hw_context *
-- 
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to