Subject: Re: unable to dump kernel core
To: Antti Kantee <>
From: Sarton O'Brien <>
List: tech-kern
Date: 11/05/2007 09:58:48
On Mon, 5 Nov 2007 07:26:13 am Antti Kantee wrote:
> Hi,
> For some time now I've been unable to get a kernel coredump from a system.
> At first I thought the system merely hung without panicking, but recently
> I discovered that it was in fact either "syncing disks" or "dumping to .."
> which made the system hang (this was fairly difficult to see from X).
> I tried it in qemu also with the same result.  It seems that the I/O
> for reading the swap device disklable never finishes and it is waited
> for indefinitely:
> #0  biowait (bp=0xcacd1a78) at ../../../../kern/vfs_bio.c:1351
> #1  0xc03218c1 in read_sector (a=0xcac45808, sector=0, count=1)
>     at ../../../../kern/subr_disk_mbr.c:115
> #2  0xc0321907 in scan_mbr (a=0xcac45808, actn=0xc0321e1a
> <look_netbsd_part>) at ../../../../kern/subr_disk_mbr.c:143
> #3  0xc0321c83 in readdisklabel (dev=11, strat=0xc0346267 <wdstrategy>,
>     lp=0xc096b600, osdep=0xc096b400) at
> ../../../../kern/subr_disk_mbr.c:293 #4  0xc034772c in wdgetdisklabel
> (wd=0xc096c800)
>     at ../../../../dev/ata/wd.c:1079
> #5  0xc0347110 in wdopen (dev=9, flag=0, fmt=24576, l=0x0)
>     at ../../../../dev/ata/wd.c:944
> #6  0xc0348652 in wdsize (dev=9) at ../../../../dev/ata/wd.c:1537
> #7  0xc0324472 in dumpsys () at ../../../../arch/i386/i386/machdep.c:1110
> #8  0xc0323fa0 in cpu_reboot (howto=256, bootstr=0x0)
>     at ../../../../arch/i386/i386/machdep.c:853
> #9  0xc0284dac in panic (fmt=0xc03dadf2 "trap")
>     at ../../../../kern/subr_prf.c:246
> Does anyone have a clue?  I can't exactly say when the last working
> -current dumping date was, but it was month(s) ago.  Does anyone even
> have similar problems?  Some people have reported that kernel coredumps
> work just fine for them.

I see the same kind of hang but admittedly I am trying the new dump to raid1. 
I just assumed some buggy code and moved on ... seeing as it didn't blow away 
any data I was content :)

NetBSD xen.cre.local 4.99.33 NetBSD 4.99.33 (XEN3_DOM0) #0: Sun Oct 14 
00:49:25 EST 2007  
root@gogeta2.internal:/usr/obj/sys/arch/i386/compile/XEN3_DOM0 i386