Commit b549c252 authored Feb 25, 2020 by Tina Zhang Committed by Zhenyu Wang Feb 25, 2020

drm/i915/gvt: Fix orphan vgpu dmabuf_objs' lifetime



Deleting dmabuf item's list head after releasing its container can lead
to KASAN-reported issue:

  BUG: KASAN: use-after-free in __list_del_entry_valid+0x15/0xf0
  Read of size 8 at addr ffff88818a4598a8 by task kworker/u8:3/13119

So fix this issue by puting deleting dmabuf_objs ahead of releasing its
container.

Fixes: dfb6ae4e ("drm/i915/gvt: Handle orphan dmabuf_objs")
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200225053527.8336-2-tina.zhang@intel.com

parent 3eb55e6f

drivers/gpu/drm/i915/gvt/dmabuf.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -151,12 +151,12 @@ static void dmabuf_gem_object_free(struct kref *kref)
		dmabuf_obj = container_of(pos,
		struct intel_vgpu_dmabuf_obj, list);
		if (dmabuf_obj == obj) {
		list_del(pos);
		intel_gvt_hypervisor_put_vfio_device(vgpu);
		idr_remove(&vgpu->object_idr,
		dmabuf_obj->dmabuf_id);
		kfree(dmabuf_obj->info);
		kfree(dmabuf_obj);
		list_del(pos);
		break;
		}
		}

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