Index: head/share/man/man9/g_attach.9
===================================================================
--- head/share/man/man9/g_attach.9
+++ head/share/man/man9/g_attach.9
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 16, 2004
+.Dd October 10, 2020
 .Dt G_ATTACH 9
 .Os
 .Sh NAME
@@ -122,6 +122,8 @@
 .Bl -tag -width Er
 .It Bq Er ELOOP
 The operation creates a topology loop.
+.It Bq Er ENXIO
+Provider got orphaned.
 .El
 .Sh SEE ALSO
 .Xr geom 4 ,
Index: head/sys/geom/bde/g_bde.c
===================================================================
--- head/sys/geom/bde/g_bde.c
+++ head/sys/geom/bde/g_bde.c
@@ -131,7 +131,13 @@
 
 	gp = g_new_geomf(mp, "%s.bde", pp->name);
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
+	error = g_attach(cp, pp);
+	if (error != 0) {
+		g_destroy_consumer(cp);
+		g_destroy_geom(gp);
+		gctl_error(req, "could not attach consumer");
+		return;
+	}
 	error = g_access(cp, 1, 1, 1);
 	if (error) {
 		g_detach(cp);
Index: head/sys/geom/cache/g_cache.c
===================================================================
--- head/sys/geom/cache/g_cache.c
+++ head/sys/geom/cache/g_cache.c
@@ -673,9 +673,11 @@
 	gp->orphan = g_cache_orphan;
 	gp->access = g_cache_access;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_cache_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_cache_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/concat/g_concat.c
===================================================================
--- head/sys/geom/concat/g_concat.c
+++ head/sys/geom/concat/g_concat.c
@@ -718,9 +718,11 @@
 	gp->access = g_concat_access;
 	gp->orphan = g_concat_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_concat_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_concat_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/geom_dev.c
===================================================================
--- head/sys/geom/geom_dev.c
+++ head/sys/geom/geom_dev.c
@@ -346,7 +346,7 @@
 	cp->private = sc;
 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
 	error = g_attach(cp, pp);
-	KASSERT(error == 0,
+	KASSERT(error == 0 || error == ENXIO,
 	    ("g_dev_taste(%s) failed to g_attach, err=%d", pp->name, error));
 
 	make_dev_args_init(&args);
Index: head/sys/geom/geom_subr.c
===================================================================
--- head/sys/geom/geom_subr.c
+++ head/sys/geom/geom_subr.c
@@ -896,6 +896,8 @@
 	G_VALID_PROVIDER(pp);
 	g_trace(G_T_TOPOLOGY, "g_attach(%p, %p)", cp, pp);
 	KASSERT(cp->provider == NULL, ("attach but attached"));
+	if ((pp->flags & (G_PF_ORPHAN | G_PF_WITHER)) != 0)
+		return (ENXIO);
 	cp->provider = pp;
 	cp->flags &= ~G_CF_ORPHAN;
 	LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
Index: head/sys/geom/geom_vfs.c
===================================================================
--- head/sys/geom/geom_vfs.c
+++ head/sys/geom/geom_vfs.c
@@ -260,7 +260,11 @@
 	sc->sc_bo = bo;
 	gp->softc = sc;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
+	error = g_attach(cp, pp);
+	if (error) {
+		g_wither_geom(gp, ENXIO);
+		return (error);
+	}
 	error = g_access(cp, 1, wr, wr);
 	if (error) {
 		g_wither_geom(gp, ENXIO);
Index: head/sys/geom/journal/g_journal.c
===================================================================
--- head/sys/geom/journal/g_journal.c
+++ head/sys/geom/journal/g_journal.c
@@ -2483,9 +2483,11 @@
 	/* This orphan function should be never called. */
 	gp->orphan = g_journal_taste_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_journal_metadata_read(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_journal_metadata_read(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/label/g_label.c
===================================================================
--- head/sys/geom/label/g_label.c
+++ head/sys/geom/label/g_label.c
@@ -400,7 +400,8 @@
 	gp->access = g_label_access_taste;
 	gp->orphan = g_label_orphan_taste;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
+	if (g_attach(cp, pp) != 0)
+		goto end2;
 	if (g_access(cp, 1, 0, 0) != 0)
 		goto end;
 	for (i = 0; g_labels[i] != NULL; i++) {
@@ -425,6 +426,7 @@
 	g_access(cp, -1, 0, 0);
 end:
 	g_detach(cp);
+end2:
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	return (NULL);
Index: head/sys/geom/linux_lvm/g_linux_lvm.c
===================================================================
--- head/sys/geom/linux_lvm/g_linux_lvm.c
+++ head/sys/geom/linux_lvm/g_linux_lvm.c
@@ -543,11 +543,13 @@
 	/* This orphan function should be never called. */
 	gp->orphan = g_llvm_taste_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_llvm_read_label(cp, &ll);
-	if (!error)
-		error = g_llvm_read_md(cp, &md, &ll);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_llvm_read_label(cp, &ll);
+		if (error == 0)
+			error = g_llvm_read_md(cp, &md, &ll);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/mirror/g_mirror.c
===================================================================
--- head/sys/geom/mirror/g_mirror.c
+++ head/sys/geom/mirror/g_mirror.c
@@ -3241,9 +3241,11 @@
 	 */
 	gp->orphan = g_mirror_taste_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_mirror_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_mirror_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/mirror/g_mirror_ctl.c
===================================================================
--- head/sys/geom/mirror/g_mirror_ctl.c
+++ head/sys/geom/mirror/g_mirror_ctl.c
@@ -449,7 +449,11 @@
 			g_topology_unlock();
 			return;
 		}
-		g_attach(cp, pp);
+		if (g_attach(cp, pp) != 0) {
+			G_MIRROR_DEBUG(1, "Can't attach disk %s.", pp->name);
+			gctl_error(req, "Can't attach disk %s.", pp->name);
+			goto err;
+		}
 		if (g_access(cp, 1, 0, 0) != 0) {
 			G_MIRROR_DEBUG(1, "Can't open disk %s.", pp->name);
 			gctl_error(req, "Can't open disk %s.", pp->name);
Index: head/sys/geom/mountver/g_mountver.c
===================================================================
--- head/sys/geom/mountver/g_mountver.c
+++ head/sys/geom/mountver/g_mountver.c
@@ -586,7 +586,12 @@
 		return (NULL);
 
 	cp = LIST_FIRST(&gp->consumer);
-	g_attach(cp, pp);
+	error = g_attach(cp, pp);
+	if (error != 0) {
+		G_MOUNTVER_DEBUG(0, "Cannot attach to %s; error = %d.", pp->name, error);
+		return (NULL);
+	}
+
 	error = g_mountver_ident_matches(gp);
 	if (error != 0) {
 		g_detach(cp);
Index: head/sys/geom/multipath/g_multipath.c
===================================================================
--- head/sys/geom/multipath/g_multipath.c
+++ head/sys/geom/multipath/g_multipath.c
@@ -823,9 +823,11 @@
 	gp->access = g_multipath_access;
 	gp->orphan = g_multipath_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_multipath_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_multipath_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/raid/g_raid.c
===================================================================
--- head/sys/geom/raid/g_raid.c
+++ head/sys/geom/raid/g_raid.c
@@ -2228,7 +2228,8 @@
 	gp->orphan = g_raid_taste_orphan;
 	cp = g_new_consumer(gp);
 	cp->flags |= G_CF_DIRECT_RECEIVE;
-	g_attach(cp, pp);
+	if (g_attach(cp, pp) != 0)
+		goto ofail2;
 	if (g_access(cp, 1, 0, 0) != 0)
 		goto ofail;
 
@@ -2251,6 +2252,7 @@
 		(void)g_access(cp, -1, 0, 0);
 ofail:
 	g_detach(cp);
+ofail2:
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	G_RAID_DEBUG(2, "Tasting provider %s done.", pp->name);
Index: head/sys/geom/raid3/g_raid3.c
===================================================================
--- head/sys/geom/raid3/g_raid3.c
+++ head/sys/geom/raid3/g_raid3.c
@@ -3315,9 +3315,11 @@
 	/* This orphan function should be never called. */
 	gp->orphan = g_raid3_taste_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_raid3_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_raid3_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/shsec/g_shsec.c
===================================================================
--- head/sys/geom/shsec/g_shsec.c
+++ head/sys/geom/shsec/g_shsec.c
@@ -646,9 +646,11 @@
 	gp->access = g_shsec_access;
 	gp->orphan = g_shsec_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_shsec_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_shsec_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/stripe/g_stripe.c
===================================================================
--- head/sys/geom/stripe/g_stripe.c
+++ head/sys/geom/stripe/g_stripe.c
@@ -963,9 +963,11 @@
 	gp->access = g_stripe_access;
 	gp->orphan = g_stripe_orphan;
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = g_stripe_read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = g_stripe_read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
 	if (error != 0)
Index: head/sys/geom/virstor/g_virstor.c
===================================================================
--- head/sys/geom/virstor/g_virstor.c
+++ head/sys/geom/virstor/g_virstor.c
@@ -780,9 +780,11 @@
 	gp->orphan = (void *)invalid_call;	/* I really want these to fail. */
 
 	cp = g_new_consumer(gp);
-	g_attach(cp, pp);
-	error = read_metadata(cp, &md);
-	g_detach(cp);
+	error = g_attach(cp, pp);
+	if (error == 0) {
+		error = read_metadata(cp, &md);
+		g_detach(cp);
+	}
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);