diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index ef868619ab..2d8763a549 100644
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -323,8 +323,10 @@ ddt_phys_addref(ddt_phys_t *ddp)
 void
 ddt_phys_decref(ddt_phys_t *ddp)
 {
-	ASSERT((int64_t)ddp->ddp_refcnt > 0);
-	ddp->ddp_refcnt--;
+	if (ddp) {
+		ASSERT((int64_t)ddp->ddp_refcnt > 0);
+		ddp->ddp_refcnt--;
+	}
 }
 
 void
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 77b1764d74..0622553f5f 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -2249,8 +2249,11 @@ zio_ddt_free(zio_t *zio)
 
 	ddt_enter(ddt);
 	freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
-	ddp = ddt_phys_select(dde, bp);
-	ddt_phys_decref(ddp);
+	if (dde) {
+		ddp = ddt_phys_select(dde, bp);
+		if (ddp)
+			ddt_phys_decref(ddp);
+	}
 	ddt_exit(ddt);
 
 	return (ZIO_PIPELINE_CONTINUE);