drm/radeon: take a BO reference on VM cleanup

This closes a small window where the GPU might have accessed freed up memory.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_vm.c b/drivers/gpu/drm/radeon/radeon_vm.c
index 759038800d10..d520ab71b748 100644
--- a/drivers/gpu/drm/radeon/radeon_vm.c
+++ b/drivers/gpu/drm/radeon/radeon_vm.c
@@ -450,6 +450,7 @@ int radeon_vm_bo_set_addr(struct radeon_device *rdev,
                         tmp->it.last = bo_va->it.last;
                         tmp->vm = vm;
                         tmp->addr = bo_va->addr;
+                        tmp->bo = radeon_bo_ref(bo_va->bo);
                         list_add(&tmp->vm_status, &vm->freed);
                 }
 
@@ -932,6 +933,7 @@ int radeon_vm_clear_freed(struct radeon_device *rdev,
 
         list_for_each_entry_safe(bo_va, tmp, &vm->freed, vm_status) {
                 r = radeon_vm_bo_update(rdev, bo_va, NULL);
+                radeon_bo_unref(&bo_va->bo);
                 kfree(bo_va);
                 if (r)
                         return r;
@@ -987,7 +989,7 @@ void radeon_vm_bo_rmv(struct radeon_device *rdev,
         list_del(&bo_va->vm_status);
 
         if (bo_va->addr) {
-                bo_va->bo = NULL;
+                bo_va->bo = radeon_bo_ref(bo_va->bo);
                 list_add(&bo_va->vm_status, &vm->freed);
         } else {
                 kfree(bo_va);
@@ -1098,8 +1100,10 @@ void radeon_vm_fini(struct radeon_device *rdev, struct radeon_vm *vm)
                         kfree(bo_va);
                 }
         }
-        list_for_each_entry_safe(bo_va, tmp, &vm->freed, vm_status)
+        list_for_each_entry_safe(bo_va, tmp, &vm->freed, vm_status) {
+                radeon_bo_unref(&bo_va->bo);
                 kfree(bo_va);
+        }
 
         for (i = 0; i < radeon_vm_num_pdes(rdev); i++)
                 radeon_bo_unref(&vm->page_tables[i].bo);