diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 037ecfde3e..c8076b1780 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -647,7 +647,7 @@ static int
 visit_indirect(spa_t *spa, const dnode_phys_t *dnp,
     blkptr_t *bp, const zbookmark_t *zb)
 {
-	int err;
+	int err = 0;
 
 	if (bp->blk_birth == 0)
 		return (0);
diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index ea78254f2d..7fb6aa6dbd 100644
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -542,7 +542,7 @@ zfs_do_create(int argc, char **argv)
 {
 	zfs_type_t type = ZFS_TYPE_FILESYSTEM;
 	zfs_handle_t *zhp = NULL;
-	uint64_t volsize;
+	uint64_t volsize = 0;
 	int c;
 	boolean_t noreserve = B_FALSE;
 	boolean_t bflag = B_FALSE;
@@ -4208,6 +4208,7 @@ main(int argc, char **argv)
 			(void) fprintf(stderr, gettext("unrecognized "
 			    "command '%s'\n"), cmdname);
 			usage(B_FALSE);
+			ret = 1;
 		}
 	}
 
diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c
index 460c27bc5c..18a402aa6f 100644
--- a/cmd/zpool/zpool_main.c
+++ b/cmd/zpool/zpool_main.c
@@ -1373,7 +1373,7 @@ zpool_do_import(int argc, char **argv)
 	char **searchdirs = NULL;
 	int nsearch = 0;
 	int c;
-	int err;
+	int err = 1;
 	nvlist_t *pools = NULL;
 	boolean_t do_all = B_FALSE;
 	boolean_t do_destroyed = B_FALSE;
@@ -3942,6 +3942,7 @@ main(int argc, char **argv)
 		(void) fprintf(stderr, gettext("unrecognized "
 		    "command '%s'\n"), cmdname);
 		usage(B_FALSE);
+		ret = 1;
 	}
 
 	libzfs_fini(g_zfs);
diff --git a/cmd/zpool/zpool_vdev.c b/cmd/zpool/zpool_vdev.c
index f8d16136ee..c82c7b3d18 100644
--- a/cmd/zpool/zpool_vdev.c
+++ b/cmd/zpool/zpool_vdev.c
@@ -552,7 +552,7 @@ get_replication(nvlist_t *nvroot, boolean_t fatal)
 	uint_t c, children;
 	nvlist_t *nv;
 	char *type;
-	replication_level_t lastrep, rep, *ret;
+	replication_level_t lastrep = { 0 }, rep, *ret;
 	boolean_t dontreport;
 
 	ret = safe_malloc(sizeof (replication_level_t));
diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 3bc201408b..fcfeef4dab 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -1344,7 +1344,7 @@ ztest_dmu_objset_create_destroy(ztest_args_t *za)
 	objects = ztest_random(20);
 	seq = 0;
 	while (objects-- != 0) {
-		uint64_t object;
+		uint64_t object = 0;
 		dmu_tx_t *tx = dmu_tx_create(os);
 		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, sizeof (name));
 		error = dmu_tx_assign(tx, TXG_WAIT);
diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index c02123b984..f2adf36ea8 100644
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -1617,7 +1617,7 @@ zfs_perm_get(zfs_handle_t *zhp, zfs_allow_t **zfs_perms)
 	char *nvpname;
 	uid_t	uid;
 	gid_t	gid;
-	avl_tree_t *tree;
+	avl_tree_t *tree = NULL;
 	avl_index_t where;
 
 	(void) strlcpy(zc.zc_name, zhp->zfs_name, sizeof (zc.zc_name));
diff --git a/lib/libzfs/libzfs_import.c b/lib/libzfs/libzfs_import.c
index 4f58ae8433..4a7634a631 100644
--- a/lib/libzfs/libzfs_import.c
+++ b/lib/libzfs/libzfs_import.c
@@ -416,7 +416,7 @@ get_configs(libzfs_handle_t *hdl, pool_list_t *pl, boolean_t active_ok)
 	pool_entry_t *pe;
 	vdev_entry_t *ve;
 	config_entry_t *ce;
-	nvlist_t *ret = NULL, *config = NULL, *tmp, *nvtop, *nvroot;
+	nvlist_t *ret = NULL, *config = NULL, *tmp = NULL, *nvtop, *nvroot;
 	nvlist_t **spares, **l2cache;
 	uint_t i, nspares, nl2cache;
 	boolean_t config_seen;
diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index b3f09b5fdf..b0662d47d3 100644
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -889,7 +889,7 @@ zprop_print_one_property(const char *name, zprop_get_cbdata_t *cbp,
     const char *source)
 {
 	int i;
-	const char *str;
+	const char *str = NULL;
 	char buf[128];
 
 	/*
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 9589006d97..ace79ad0ad 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -2609,7 +2609,7 @@ top:
 		uint64_t size = BP_GET_LSIZE(bp);
 		arc_callback_t	*acb;
 		vdev_t *vd = NULL;
-		daddr_t addr;
+		daddr_t addr = -1;
 		boolean_t devw = B_FALSE;
 
 		if (hdr == NULL) {
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index 52373e8b63..b1f3bea77a 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -189,7 +189,7 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
 	uint32_t flags;
 	int err;
 	zio_t *zio;
-	hrtime_t start;
+	hrtime_t start = 0;
 
 	ASSERT(length <= DMU_MAX_ACCESS);