SonicOS 6.5 is currently not able to handle NetBIOS names in the LDAP partitions under the Manage | Users | Settings causing the SonicWall to reboot.
When everything is configured as expected, there are no issues whereas if you add an incorrect domain, the firewall will start rebooting in bootloop. This issue has been observed on SonicOS 22.214.171.124-40n.
The following is an example:
The domain configured on the LDAP server is "subdomain.domain.com": if instead of specifying subdomain.domain.com you specify "subdomain" only or "sub.domain.com" the SonicWall will start rebooting due to tLdapAsyncTask as the domain cannot be found.
The root cause of the issue is related to the configuration of a NetBIOS name in the partitions.
Should you encounter the issue, you may have to disconnect/power off your SonicWall from the network to be able to stop the bootloop and modify the configuration to fix it. As soon as the domains are correctly configured, the SonicWall shouldn't reboot any longer. This issue is currently being treated with high priority.