Bug 22951

	
The system kernel panics approximately 2 minutes after a drive in the
array fails/disappears. Expected behavior would be for it to keep
attempting to access the drive for a while, then give up on it and
continue running off the remaining drives in the array.

Panic messages:
Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x68
fault code              = supervisor read page not present
instruction pointer     = 0x8:0xc0166e2c
stack pointer           = 0x10:0xc02810d4
frame pointer           = 0x10:0xc0281104
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = Idle
interrupt mask          = bio
trap number             = 12
panic: page fault
                        
syncing disks...

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x30
fault code              = supervisor read page not present
instruction pointer     = 0x8:0xc0202b74
stack pointer           = 0x10:0xc0280f04
frame pointer           = 0x10:0xc0280f08
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = Idle
interrupt mask          = bio 
trap number             = 12 
panic: page fault

How-To-Repeat: 	
Install a 4.2-RC1 system onto an ar* RAID 1 array using the HPT370 chipset
(found on the Abit KT7-RAID motherboard). Disconnect power to one of
drives. System will panic within about 2 minutes.