diff --git a/sys/geom/vinum/geom_vinum_drive.c b/sys/geom/vinum/geom_vinum_drive.c
index 5ab68f39dd7..f782fd0c721 100644
--- a/sys/geom/vinum/geom_vinum_drive.c
+++ b/sys/geom/vinum/geom_vinum_drive.c
@@ -126,6 +126,10 @@ gv_read_header(struct g_consumer *cp, struct gv_hdr *m_hdr)
 	pp = cp->provider;
 	KASSERT(pp != NULL, ("gv_read_header: null pp"));
 
+	if ((GV_HDR_OFFSET % pp->sectorsize) != 0 ||
+	    (GV_HDR_LEN % pp->sectorsize) != 0)
+		return (ENODEV);
+
 	d_hdr = g_read_data(cp, GV_HDR_OFFSET, pp->sectorsize, NULL);
 	if (d_hdr == NULL)
 		return (-1);
diff --git a/sys/geom/vinum/geom_vinum_events.c b/sys/geom/vinum/geom_vinum_events.c
index fcd45f10f84..db4e5434b58 100644
--- a/sys/geom/vinum/geom_vinum_events.c
+++ b/sys/geom/vinum/geom_vinum_events.c
@@ -109,6 +109,12 @@ gv_drive_tasted(struct gv_softc *sc, struct g_provider *pp)
 	buf = NULL;
 
 	G_VINUM_DEBUG(2, "tasted drive on '%s'", pp->name);
+	if ((GV_CFG_OFFSET % pp->sectorsize) != 0 ||
+	    (GV_CFG_LEN % pp->sectorsize) != 0) {
+		G_VINUM_DEBUG(0, "provider %s has unsupported sectorsize.",
+		    pp->name);
+		return;
+	}
 
 	gp = sc->geom;
 	g_topology_lock();