[Proliant DL380p] [Centos7.1x64] Server hangs while rebooting

Hi,

I made a new oVirt installation (http://www.ovirt.org/Home) using Centos7.1x64 (all updates) on top of two HP Proliant DL380p.

When I reboot any server, it hangs with this message "hpwdt unexpected close not stopping watchdog"

I got this error on ILO4 GUI  "An unrecoverable System Error (NMI) has occured (System error code 0x0000002b,0x00000000)"

There is something wrong between the OS and HP watchdog.

After some searching, I added this line "intremap=no_x2apic_optout" to kernel parameters, but it didn't change anything.

I updated the ILO4 firmware from 1.40 to 2.10 and the SmartArray p420i from 5.10 to 6.34, but it didn't change anything.

The current BIOS version is 02/10/2014, I don't know if there is a newer one !

Any idea?

Thanks in advance.