diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
index 4c20fec64d96a0a6238be33e4d05b560e5179337..6b8f2a19b2d96b66d67915a4a91281294a3b848f 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
@@ -228,6 +228,8 @@ gk20a_instobj_release_dma(struct nvkm_memory *memory)
 	struct gk20a_instmem *imem = node->imem;
 	struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
 
+	/* in case we got a write-combined mapping */
+	wmb();
 	nvkm_ltc_invalidate(ltc);
 }