Hello, My server was using FreeBSD-7-Stable and performing a mail server. Software I used is postfix 2.6.3 and dovecot 1.2.4. The hardware is IBM blade server HS-21 CPU: dual Intel E5335 @ 2.00GHz MEM: 3G HD: onboard LSI RAID controller with 2 73G SAS HD. (mpt0: <LSILogic SAS/SATA Adapter>) The system is very stable until last week. After csup the FreeBSD-7-STABLE source to around 2009/09/10, it will halt randomly around every several hours. The error message I saw on console was the following: panic: UMA: page_free used with invalid flags 4 cpuid = 0 Uptime: 3h1m14s Physical memory: 3064MB Dumping 1544MB: 1529 1513 1497.................... Reading freebsd-stable mailing shows there is some vm related modfication during the first week of Sep. (the panic: vm_phys_paddr_to_vm_page: paddr 0x series) So, I csup my src back to 2009/09/01, the problem disappeared, and system comes back with stable state. Today, I csup my src to latest 7-STABLE (2009/09/15) and problem comes again. It seems the problem is still there and not be solved yet. Would you please help to fix it? Thanks very much. Sincerely, Tim Chen