drm/i915: Only unpin the default ctx object if it exists

Since commit 691e6415c891b8b2b082a120b896b443531c4d45
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Apr 9 09:07:36 2014 +0100

    drm/i915: Always use kref tracking for all contexts.

we have contexts everywhere, and so we must be careful to distinguish
fake contexts, which do not have an associated bo, and real ones, which
do. In particular, we now need to be careful not to dereference NULL
pointers.

This is one such example, as the commit highlighted above failed to move
the unpinning of the default ctx object into the real-context-only
branch.

Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78792
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index f7ad59e71b368c6a5ebd0d6a5af5438a4817fc08..50875f5d0c88c9ece5aca75e185ea440927707e4 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -449,6 +449,8 @@ void i915_gem_context_fini(struct drm_device *dev)
                        i915_gem_context_unreference(dctx);
                        dev_priv->ring[RCS].last_context = NULL;
                }
+
+               i915_gem_object_ggtt_unpin(dctx->obj);
        }
 
        for (i = 0; i < I915_NUM_RINGS; i++) {
@@ -461,7 +463,6 @@ void i915_gem_context_fini(struct drm_device *dev)
                ring->last_context = NULL;
        }
 
-       i915_gem_object_ggtt_unpin(dctx->obj);
        i915_gem_context_unreference(dctx);
 }