Subject: kernel crash--data modified on freelist?
To: None <current-users@NetBSD.ORG>
From: John Hawkinson <>
List: current-users
Date: 02/02/1995 04:27:42
Hi, all.

I've got a machine currently running Linux (
that I'm attempting to boot NetBSD upon. Booting off of the 1.0-dist
floppies cause it to crash and reboot (clearing the screen) a few
moments after you hit return for the "filesystem floppy". It prints
something out on the screen before it clears it (that clearing is
probably a bug -- it certainly is annoying as I haven't bothered to
try and figure out what's being printed out), and then prints more
errors before crashing 'n burning.

I've booted w/ a kernel w/ DDB and DIAGNOSTIC (and lots of other
cruft, too, but), and played with DDB for a while, and gotten
the attached. Filenames and line numbers in {{}} are added by
me from gdb; this is a 1.0 kernel...

Any help (what's wrong, how to debug, etc.) would be appreciated...

John Hawkinson

Data modified on freelist: word 2.5 of object 0xf8694fc0 size 56 previous type ?
?? (invalid addr 0xffffffff)
Data modified on freelist: word 0 of object 0xf8694fc0 size 56 previous type ???
 (0xffffffff != 0xdeadbeef)
Breakpoint at    _malloc+0x3c8: addl   $0x24,%sp	{{kern_malloc.c:221}}
db> t
_malloc(38,1f,0) at _malloc+0x3c8			{{kern_malloc.c:221}}
  at vm_map_entry_create+0x17				{{vm/vm_map.c:296}}
__vm_map_clip_end(f868ff00,f8693040,f8e97000) at __vm_map_clip_end+0x11
_vm_map_pageable(f868ff00,f8e96000,f8e97000,0,1d1fac) at _vm_map_pageable+0x1cb
_cpu_startup(f8197f04,1d1fac,1e0000,1e0000,f824b000) at _cpu_startup+0x182
_main(f7bfff8c) at _main+0x3b				{{init_main.c:129}}