drm/amdgpu: fix locking in vega10_ih_prescreen_iv

The vm pointer can become invalid as soon as the lock is released.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/vega10_ih.c

@@ -278,9 +278,9 @@ static bool vega10_ih_prescreen_iv(struct amdgpu_device *adev)
 	/* Track retry faults in per-VM fault FIFO. */
 	spin_lock(&adev->vm_manager.pasid_lock);
 	vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
-	spin_unlock(&adev->vm_manager.pasid_lock);
 	if (WARN_ON_ONCE(!vm)) {
 		/* VM not found, process it normally */
+		spin_unlock(&adev->vm_manager.pasid_lock);
 		amdgpu_ih_clear_fault(adev, key);
 		return true;
 	}
@@ -288,9 +288,11 @@ static bool vega10_ih_prescreen_iv(struct amdgpu_device *adev)
 	r = kfifo_put(&vm->faults, key);
 	if (!r) {
 		/* FIFO is full. Ignore it until there is space */
+		spin_unlock(&adev->vm_manager.pasid_lock);
 		amdgpu_ih_clear_fault(adev, key);
 		goto ignore_iv;
 	}
+	spin_unlock(&adev->vm_manager.pasid_lock);
 
 	/* It's the first fault for this address, process it normally */
 	return true;