We need to hold bdev->fence_lock while grabbing a reference to the fence, to prevent concurrent clearing/changing of the ttm_bo->sync_obj field.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/radeon/radeon_display.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c index 8724196..069d5cc 100644 --- a/drivers/gpu/drm/radeon/radeon_display.c +++ b/drivers/gpu/drm/radeon/radeon_display.c @@ -378,8 +378,12 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc, work->old_rbo = rbo; obj = new_radeon_fb->obj; rbo = gem_to_radeon_bo(obj); + + spin_lock(&rbo->tbo.bdev->fence_lock); if (rbo->tbo.sync_obj) work->fence = radeon_fence_ref(rbo->tbo.sync_obj); + spin_unlock(&rbo->tbo.bdev->fence_lock); + INIT_WORK(&work->work, radeon_unpin_work_func);
/* We borrow the event spin lock for protecting unpin_work */