drm/i915: Fix unsafe vma iteration in i915_drop_caches
When unbinding, there is a possibility that we drop the active reference
on the object, thereby freeing it. If that happens, we may destroy the
vm link as well as the object and vma. So iterate carefully.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index d8389b2..c19fbdc 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3812,8 +3812,6 @@
struct drm_device *dev = data;
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_gem_object *obj, *next;
- struct i915_address_space *vm;
- struct i915_vma *vma, *x;
int ret;
DRM_DEBUG("Dropping caches: 0x%08llx\n", val);
@@ -3834,16 +3832,23 @@
i915_gem_retire_requests(dev);
if (val & DROP_BOUND) {
- list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
- list_for_each_entry_safe(vma, x, &vm->inactive_list,
- mm_list) {
+ list_for_each_entry_safe(obj, next, &dev_priv->mm.bound_list,
+ global_list) {
+ struct i915_vma *vma, *v;
+
+ ret = 0;
+ drm_gem_object_reference(&obj->base);
+ list_for_each_entry_safe(vma, v, &obj->vma_list, vma_link) {
if (vma->pin_count)
continue;
ret = i915_vma_unbind(vma);
if (ret)
- goto unlock;
+ break;
}
+ drm_gem_object_unreference(&obj->base);
+ if (ret)
+ goto unlock;
}
}