Upgrading kernel to RHEL5.5 with EMC Clariion storage causes multipath failover to stop working

Issue

• Multipath shows all paths, and appears configured correctly, but failover does not work
• Multipath failure after upgrade in EMC Clariion multipath boot environment
• Multipath failover stops working after upgrade on EMC Clariion
• On boot from SAN (EMC Clariion) system, after upgrading the kernel from RHEL5.4 to RHEL5.5, multipath failover no longer works as expected. The system hangs when all but one path is disabled.
• At time of the failure, the following messages are seen repeated on the console:

device-mapper: multipath: Failing path 8:48.
device-mapper: multipath: Failing path 8:48.  
device-mapper: multipath: Failing path 8:48.  
device-mapper: multipath: Failing path 8:48."

• In addition, we see the following messages from dmesg:

device-mapper: multipath emc: emc\_pg\_init: sending switch-over command  
device-mapper: multipath: Failing path 8:48.