: Date: Fri, 5 Dec 1997 04:19:50 +0100 (MET)
: From: Andries.Brouwer@cwi.nl
: Made another attempt to install Redhat 5.0 (kernel 2.0.31 on Intel).
: The attempt ended in
: Kernel panic: scsi_free: Trying to free unused memory
: In swapper task - not syncing
: and the machine was dead (no console switch, CapsLock, CtrlAltDel).
: I have now seen this machine crash 3 times during a RedHat 5.0 install,
: and at least twice this was a kernel bug. Maybe 2.0.31 is no good
: (on my hardware). The third time things ended in an infinite chain
: scsi: aborting command due to timeout - resetting -
: Sent BUS DEVICE RESET - Sending DID RESET
: (repeated hundreds of times).
: cc: lnz, linux-kernel
: I don't know why you are hitting these SCSI problems. It's strange that one
: distribution would have problems and another one not.
Not so strange:
Possibility 1: the pattern of I/O accesses is different, so that
one install triggers a hardware or kernel bug that the
other avoids.
Possibility 2: the kernel is different; this particular 2.0.31 is
rotten and destroys some random memory; now anything can happen.
Statistics for 7 install attempts last night:
1x: Kernel panic: scsi_free: Trying to free unused memory
2x: Oops: 0000, EIP 0010:001a612d which translates to
do_sr_request + 189 (two almost identical Oops; more info on request)
3x: Infinite sequence of SCSI bus resets
1x: No visible traces of anything wrong; install script aborts
with unspecified error.
So, quite apart from the bad SCSI reset code, there is a kernel
bug that yields Oops, Oops, panic. So, most likely this kernel
is buggy, probably with a bug in the SCSI code.
: As for the infinite resets, I believe that the Bus Device Reset code in the
: Adaptec 1542 driver has been broken since day one. If you ever trigger that
: code, you're going to lose badly, since it doesn't actually send a Bus Device
: Reset even though it claims to.
No doubt you are right. But it is contagious: if a bad CD-ROM
triggers this resetting cycle, then soon afterwards also the
SCSI disks have problems.
Andries