diff --git a/module/os/freebsd/zfs/vdev_label_os.c b/module/os/freebsd/zfs/vdev_label_os.c
index 338982ff68..79732d9173 100644
--- a/module/os/freebsd/zfs/vdev_label_os.c
+++ b/module/os/freebsd/zfs/vdev_label_os.c
@@ -55,8 +55,8 @@ vdev_label_write_pad2(vdev_t *vd, const char *buf, size_t size)
 	ASSERT3U(spa_config_held(spa, SCL_ALL, RW_WRITER), ==, SCL_ALL);
 
 	pad2 = abd_alloc_for_io(VDEV_PAD_SIZE, B_TRUE);
-	abd_zero(pad2, VDEV_PAD_SIZE);
 	abd_copy_from_buf(pad2, buf, size);
+	abd_zero_off(pad2, size, VDEV_PAD_SIZE - size);
 
 retry:
 	zio = zio_root(spa, NULL, NULL, flags);
diff --git a/module/zfs/mmp.c b/module/zfs/mmp.c
index 25eea07529..66bc0ae60b 100644
--- a/module/zfs/mmp.c
+++ b/module/zfs/mmp.c
@@ -517,8 +517,9 @@ mmp_write_uberblock(spa_t *spa)
 
 	zio_t *zio  = zio_null(mmp->mmp_zio_root, spa, NULL, NULL, NULL, flags);
 	abd_t *ub_abd = abd_alloc_for_io(VDEV_UBERBLOCK_SIZE(vd), B_TRUE);
-	abd_zero(ub_abd, VDEV_UBERBLOCK_SIZE(vd));
 	abd_copy_from_buf(ub_abd, ub, sizeof (uberblock_t));
+	abd_zero_off(ub_abd, sizeof (uberblock_t),
+	    VDEV_UBERBLOCK_SIZE(vd) - sizeof (uberblock_t));
 
 	mmp->mmp_seq++;
 	mmp->mmp_kstat_id++;
diff --git a/module/zfs/vdev_label.c b/module/zfs/vdev_label.c
index e8f562a1a6..4c6501cc9a 100644
--- a/module/zfs/vdev_label.c
+++ b/module/zfs/vdev_label.c
@@ -1187,8 +1187,9 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 	 * Initialize uberblock template.
 	 */
 	ub_abd = abd_alloc_linear(VDEV_UBERBLOCK_RING, B_TRUE);
-	abd_zero(ub_abd, VDEV_UBERBLOCK_RING);
 	abd_copy_from_buf(ub_abd, &spa->spa_uberblock, sizeof (uberblock_t));
+	abd_zero_off(ub_abd, sizeof (uberblock_t),
+	    VDEV_UBERBLOCK_RING - sizeof (uberblock_t));
 	ub = abd_to_buf(ub_abd);
 	ub->ub_txg = 0;
 
@@ -1767,8 +1768,9 @@ vdev_uberblock_sync(zio_t *zio, uint64_t *good_writes,
 
 	/* Copy the uberblock_t into the ABD */
 	abd_t *ub_abd = abd_alloc_for_io(VDEV_UBERBLOCK_SIZE(vd), B_TRUE);
-	abd_zero(ub_abd, VDEV_UBERBLOCK_SIZE(vd));
 	abd_copy_from_buf(ub_abd, ub, sizeof (uberblock_t));
+	abd_zero_off(ub_abd, sizeof (uberblock_t),
+	    VDEV_UBERBLOCK_SIZE(vd) - sizeof (uberblock_t));
 
 	for (int l = 0; l < VDEV_LABELS; l++)
 		vdev_label_write(zio, vd, l, ub_abd,