[PATCH] drm/i915/vma: Correct use after free in eviction

Ben Widawsky
2013-08-16T17:44:13Z

The vma will [possibly] be destroyed during unbind in eviction.
Immediately after this, we try to delete the list entry.

Chris and Ville did the debug on this before I woke up, I just get to
take credit for the fix :p

Reported-by: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
drivers/gpu/drm/i915/i915_gem_evict.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 0cbaad4..db90261 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -139,10 +139,11 @@ found:
vma = list_first_entry(&eviction_list,
struct i915_vma,
exec_list);
+
+ list_del_init(&vma->exec_list);
if (ret == 0)
ret = i915_vma_unbind(vma);

- list_del_init(&vma->exec_list);
drm_gem_object_unreference(&vma->obj->base);
}

--
1.8.3.4