Autofs hangs

[Steve Thompson <smt@vgersoft.com>]

CentOS 5.5, 32- and 64-bit. Maps from LDAP. I upgraded recently (as part 
of a system-wide yum update) from autofs-5.0.1-0.rc2.143.el5_5.4 to 
autofs-5.0.1-0.rc2.143.el5_5.6, and ever since I have had a MASSIVE number 
of automount hangs (several per day across 170 systems). Nothing is 
logged, and the automount deamon is hung solid; only a SIGKILL and a 
restart can recover the daemon (and, if I wasn't already logged in, a 
power cycle is required - all accounts use automounted NFS home 
directories). Reading the Changelog, I see these changes:

- add mutex to serialize access to mount module handle in parse module
- dont check null cache on expire
- fix null cache race
- fix cache_init() on source re-read
- fix negative cache included map lookup

I don't know which of these to point the finger at, but I have also 
noticed many messages similar to:

automount<pid>]: update_negative_cache: key "<pid>" not found in map.

all of which are incorrect. Really need a fix for this asap - we're 
almost dead in the water.

-smt