>Number:         31981
>Category:       kern
>Synopsis:       stopping scsi disk can cause panic
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Nov 02 15:51:00 +0000 2005
>Originator:     Pavel Cahyna
>Release:        NetBSD 3.0_BETA
>Organization:
>Environment:
System: NetBSD beta 3.0_BETA NetBSD 3.0_BETA (BETA) #4: Fri Oct 7 21:20:07 CEST 2005 root@beta:/usr/src/sys/arch/alpha/compile/BETA alpha
Architecture: alpha
Machine: alpha
>Description:

I tried the "scsictl ... stop" command to hear how noisy each disk is.
Some time after issuing it on the root drive, the machine paniced.

relevant pieces of dmesg:

esiop0 at pci0 dev 7 function 0: Symbios Logic 53c875 (ultra-wide scsi)
esiop0: using on-board RAM
esiop0: interrupting at eb164 irq 1
scsibus0 at esiop0: 16 targets, 8 luns per target
...
scsibus0: waiting 2 seconds for devices to settle...
sd0 at scsibus0 target 0 lun 0: <IBM, DNES-309170W, SA30> disk fixed
sd0: 8748 MB, 11474 cyl, 5 head, 312 sec, 512 bytes/sect x 17916240 sectors
sd0: sync (50.00ns offset 16), 16-bit (40.000MB/s) transfers, tagged queueing
sd1 at scsibus0 target 2 lun 0: <SEAGATE, ST318437LW, 0102> disk fixed
sd1: 17547 MB, 29851 cyl, 2 head, 601 sec, 512 bytes/sect x 35937500 sectors
sd1: sync (50.00ns offset 16), 16-bit (40.000MB/s) transfers, tagged queueing
cd0 at scsibus0 target 5 lun 0: <YAMAHA, CRW6416S, 1.0c> cdrom removable
cd0: sync (100.00ns offset 15), 8-bit (10.000MB/s) transfers
root on sd0a dumps on sd0b
root file system type: ffs
sd0(esiop0:0:0:0):  Check Condition on CDB: 0x2a 00 00 e0 19 40 00 00 20 00
    SENSE KEY:  Not Ready
     ASC/ASCQ:  Logical Unit Not Ready, Initialization Command Required

/: got error 5 while accessing filesystem
panic: softdep_deallocate_dependencies: unrecovered I/O error
sd0(esiop0:0:0:0):  Check Condition on CDB: 0x35 00 00 00 00 00 00 00 00 00
    SENSE KEY:  Not Ready
     ASC/ASCQ:  Logical Unit Not Ready, Initialization Command Required

sd0: cache synchronization failed
rebooting...

>How-To-Repeat:
see above.
>Fix:
start the disk and restart the I/O if this error is received?
During boot, NetBSD can start the disk without problems.