panic: vm_fault: fault on nofault entry in ATA code(?)

I have an old (Pentium-166) machine with two 212Mb IDE disks (more info attached) in CCD set. It was not in use for about a year (it was running FreeBSD 5-CURRENT around mid-june 2003) and now I decide to upgrade it to latest -CURRENT (from 1st May, to be precise). Now I'm getting panic after attempt to fsck /dev/ccd0 after several ata FAILUREs:


atapci0: <Intel PIIX3 WDMA2 controller> port 0xe800-0xe80f,0x376,0x170-0x177,0x3f6,0x1f0-0x1f7 at device 7.1 on pci0
atapci0: Reserved 0x10 bytes for rid 0x20 type 4 at 0xe800
atapci0: Reserved 0x8 bytes for rid 0x10 type 4 at 0x1f0
atapci0: Reserved 0x1 bytes for rid 0x14 type 4 at 0x3f6
ata0: at 0x1f0 irq 14 on atapci0
atapci0: Reserved 0x8 bytes for rid 0x18 type 4 at 0x170
atapci0: Reserved 0x1 bytes for rid 0x1c type 4 at 0x376
ata1: at 0x170 irq 15 on atapci0
[...]
ad0: 535MB <SAMSUNG SHD-30560A (APRO-5) SSI> [1087/16/63] at ata0-master WDMA0
ata1-master: FAILURE - SETFEATURES SET TRANSFER MODE status=51<READY,DSC,ERROR> error=4<ABORTED>
ad2: FAILURE - SETFEATURES DISABLE WCACHE status=51<READY,DSC,ERROR> error=4<ABORTED>
ad2: 202MB <WDC AC2200F> [989/12/35] at ata1-master BIOSPIO
ad3: 202MB <WDC AC1210F> [989/12/35] at ata1-slave PIO3
Mounting root from ufs:/dev/ad0s1a
Enter full pathname of shell or RETURN for /bin/sh:
# ccdconfig -C
# fsck -t ufs /dev/ccd0
** /dev/ccd0
ad2: TIMEOUT - READ retrying (2 retries left) LBA=33554443
ad2: FAILURE - SETFEATURES SET TRANSFER MODE status=51<READY,DSC,ERROR> error=4<ABORTED>
ad2: FAILURE - SETFEATURES DISABLE WCACHE status=51<READY,DSC,ERROR> error=4<ABORTED>
ad2: FAILURE - SETFEATURES SET TRANSFER MODE status=51<READY,DSC,ERROR> error=4<ABORTED>
panic: vm_fault: fault on nofault entry, addr: c2e2d000
at line 277 in file /usr/src/sys/vm/vm_fault.c
Debugger("panic")
Stopped at      Debugger+0x45:  xchgl   %ebx,in_Debugger.0
db> t
Debugger(c05a7229) at Debugger+0x45
__panic(c05b706f,115,c05b708a,c2e2d000,5) at __panic+0xc7
vm_fault(c0c3b000,c2e2d000,2,0,c0cd0160) at vm_fault+0xe38
trap_pfault(c330ac68,0,c2e2d000) at trap_pfault+0x124
trap(18,10,10,c2e2d000,c14bfe00) at trap+0x2f9
calltrap() at calltrap+0x5
--- trap 0xc, eip = 0xc042ec82, esp = 0xc330aca8, ebp = 0xc330acc8 ---
ata_pio_read(c151f000,200) at ata_pio_read+0xba
ata_generic_interrupt(c14bfe00) at ata_generic_interrupt+0x2c2
ithread_loop(c0cc4600,c330ad48,c0cc4600,c047a118,0) at ithread_loop+0x1a4
fork_exit(c047a118,c0cc4600,c330ad48) at fork_exit+0xa8
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xc330ad7c, ebp = 0 ---
db>