diff --git a/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c b/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c
index 1a2c2ac0fd98..ef386968e858 100644
--- a/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c
+++ b/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c
@@ -650,6 +650,9 @@ dprintf_setup(int *argc, char **argv)
 	 */
 	if (dprintf_find_string("on"))
 		dprintf_print_all = 1;
+
+	if (dprintf_string != NULL)
+		zfs_flags |= ZFS_DEBUG_DPRINTF;
 }
 
 int