kern/41243: kernel core dump produces unusable core

[hramrach%centrum.cz@localhost]

>Number:         41243
>Category:       kern
>Synopsis:       kernel core dump produces unusable core
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Apr 17 20:55:00 +0000 2009
>Originator:     Michal Suchanek
>Release:        5.0 RC3
>Organization:
>Environment:
NetBSD  5.0_RC3 NetBSD 5.0_RC3 (Dell_CPxJ) #0: Tue Apr 14 10:54:55 CEST 2009  
root@:/usr/src/sys/arch/i386/compile/Dell6
>Description:
Following the faq I tried to examine a kernel core dump with gdb.

However, the result of running bt in the kernel debugger and in gdb while 
examinig the core file produces very different results.



syncing disks... done
unmounting file systems...
unmounting /dev/pts (ptyfs)...
unmounting /kern (kernfs)...  
unmounting /home (/dev/wd0f)...
unmounting / (/dev/wd0a)... done
panic: cpu_switchto: switching above IPL_SCHED (8)
fatal breakpoint trap in supervisor mode          
trap type 1 code 0 eip c05331ac cs 8 eflags 246 cr2 bbbc0a80 ilevel 8
Stopped in pid 316.1 (reboot) at        netbsd:breakpoint+0x4:  popl    %ebp
db{0}> bt                                                                   
breakpoint(c07cbdf2,cb3cda90,c07e8240,c0f9dac6,cb3cda6c,c0454b7c,ca219040,cb3e4d
40,cb3cda9c,c0524dfa) at netbsd:breakpoint+0x4                                  
panic(c0100391,8,ca23fd00,ca7d4524,0,c0454d5d,cb3e4d40,ca23fd00,0,c0451730) at n
etbsd:panic+0x1b0                                                               
cpu_switchto(cb3e4d40,4,4,c07b06fa,0,7d4658,1,10,ca7d4524,0) at netbsd:cpu_switc
hto+0x1e                                                                        
sleepq_block(4,0,c07b06fa,4,0,44,4,ca7d4658,2,1) at netbsd:sleepq_block+0xeb
pccbb_power(ca7d4524,c0fb5b2c,cb3cdb9c,c05efd01,ca7d4edc,cb08c008,cb3cdbbc,c05f3
7d8,ca7d4524,0) at netbsd:pccbb_power+0x302                                     
pccbb_pcmcia_socket_disable(ca7d4524,0,cb3cdbcc,c0592595,cb08c008,cb08c008,cb3cd
bcc,c02866b3,cb08c008,e29) at netbsd:pccbb_pcmcia_socket_disable+0x41           
ep_pcmcia_disable(cb08c008,e29,cb3cdbfc,c028843d,cb08c008,4000,e,0,c0861280,cb08
c008) at netbsd:ep_pcmcia_disable+0x18                                          
epdisable(cb08c008,4000,e,0,c0861280,cb08c008,8,0,cb3cdd00,c07e3d20) at netbsd:e
pdisable+0x23                                                                   
epshutdown(cb08c008,0,cb3cdc2c,c053994b,8,cb3e4d40,0,0,cb3cdd00,0) at netbsd:eps
hutdown+0xbd                                                                    
doshutdownhooks(8,cb3e4d40,0,0,cb3cdd00,0,cb3cdcdc,c0460aa4,0,0) at netbsd:doshu
tdownhooks+0x2a                                                                 
cpu_reboot(0,0,0,0,0,0,cb3cdc9c,c05267ef,23,cb3cdcc0) at netbsd:cpu_reboot+0x1b
sys_reboot(cb3e4d40,cb3cdd00,cb3cdd28,cb3cdd40,c052679d,ca23af60,1,0,0,bfbfeb38)
 at netbsd:sys_reboot+0x74
syscall(cb3cdd48,b3,ab,1f,1f,1,d,bfbfeb38,2,256) at netbsd:syscall+0xc8



# gdb /netbsd.gdb
GNU gdb 6.5
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386--netbsdelf"...
(gdb) target kvm /var/crash/netbsd.2.core
#0  0xc05399f2 in cpu_reboot (howto=260, bootstr=0x0)
    at ../../../../arch/i386/i386/machdep.c:926
926                     dumpsys();
(gdb) bt
#0  0xc05399f2 in cpu_reboot (howto=260, bootstr=0x0)
    at ../../../../arch/i386/i386/machdep.c:926
#1  0xc04727e0 in panic (
    fmt=0xc0100391 "cpu_switchto: switching above IPL_SCHED (%d)")
    at ../../../../kern/subr_prf.c:253
#2  0xc010038e in cpu_switchto ()
#3  0xca7d4524 in ?? ()
#4  0x00000000 in ?? ()

>How-To-Repeat:
Crash netbsd

run 'bt' in the kernel debugger

save the core

reboot

run 'bt' in gdb

# gunzip /var/crash/netbsd.0.core.gz
# gdb netbsd.gdb
(gdb) target kvm /var/crash.netbsd.0.core
(gdb) bt
>Fix: