Date: Sun, 27 Aug 1995 21:14:51 +0200 (MET DST) From: hm@ernie.altona.hamburg.com (Hellmuth Michaelis) To: freebsd-hackers@freebsd.org (FreeBSD Hackers) Subject: SCSI CDROM autochanger access causes fatal trap 12 Message-ID: <m0smnAS-00000vC@ernie.altona.hamburg.com>
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Since some weeks i own a 7 disk CDROM autochanger, and i eventually got it
to be recognized and run on a plain 2.0.5 by using NEW_SCSICONF in the kernel
config file.
The individual CD's are accessed by talking to the 7 SCSI LUN's.
After mounting and/or dismounting several CD's from different LUN's (i tried
to check if there is a limit on the number of CD's touched, but there isn't:
somtimes it happenes when i mount CD 1..4, sometimes it happenes when i mount
CD 1..6) the system panics when the next write (!) is done to a (normal r/w)
SCSI disk drive:
Fatal trap 12: page fault while in kernel mode
Fault virtual address = 0x60
Fault code = supervisor read, page not present
Instruction pointer = 0x8:0xf01250ac
Code segment = base 0x0 limit 0xfffff type 0x1b
= DPL 0, pres 1, def 321, gran 1
Processor eflags = interrupt enabled, resume, IOPL = 0
Current process = 470 (iozone)
Interrupt mask = bio
Kernel: type 12 trap, code = 0
Stopped at _incore+0x48: cmpl %esi, 0x48(%ebx)
This is fully reproducible, i just used iozone to trigger the write, any other
program writing to disk does also.
I had a serious look at incore() in vfs_bio.c, but i'm not that filesystem
hacker to really and fully understand what happenes but i'd like to see this
bug fixed.
What can i do ? Is someone willing to help a bit to find the cause ?
hellmuth
--
Hellmuth Michaelis hm@altona.hamburg.com Hamburg, Europe
(A)bort, (R)etry, (I)nstall BSD ?
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