[PATCH 5.4 097/152] drm/i915/gvt: Fix orphan vgpu dmabuf_objs lifetime

Greg Kroah-Hartman
2020-03-03T17:57:52Z

From: Tina Zhang <tina.zhang@intel.com>

commit b549c252b1292aea959cd9b83537fcb9384a6112 upstream.

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: dfb6ae4e14bd6 ("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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/i915/gvt/dmabuf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/gvt/dmabuf.c
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
@@ -96,12 +96,12 @@ static void dmabuf_gem_object_free(struc
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;
}
}