Worth persuing a KDB: stack backtrace: ?

[Jeremy Chadwick]

On Sat, Oct 11, 2008 at 11:22:21AM -0400, Tuc wrote:
> 	I have a 5.5-STABLE laptop thats been having issues lately, mostly
> related to memory. I bought new chips, and I think I narrowed it down to one
> of the Dimm slots being bad. I did a memtest for 25 hours and it seemed stable.

memtest86+ would definitely detect a DIMM slot being bad, so running it
for 25 hours successfully means the DIMM and the DIMM slot is likely fine.

> I started up and started downloading a backup of over 5K emails. (All have
> to go through mimedefang, procmail and sendmail... So the system was a bit
> sluggish. I started to get things like :
> 
> Oct 10 22:06:29 himinbjorg kernel: KDB: stack backtrace:
> Oct 10 22:06:29 himinbjorg kernel: kdb_backtrace(c3053200,1,dbb54c04,dbb54bf0,c0
> 73ba78) at kdb_backtrace+0x29
> Oct 10 22:06:29 himinbjorg kernel: getdirtybuf(dbb54be0,0,1,cc1c81e8,1) at getdi
> rtybuf+0x27
> Oct 10 22:06:29 himinbjorg kernel: flush_deplist(c305354c,1,dbb54c04) at flush_d
> eplist+0x34
> Oct 10 22:06:29 himinbjorg kernel: flush_inodedep_deps(c216d000,715e,c089bcf8,c0
> 808b16,ef) at flush_inodedep_deps+0x7d
> Oct 10 22:06:29 himinbjorg kernel: softdep_sync_metadata(dbb54ca0) at softdep_sy
> nc_metadata+0x8c
> Oct 10 22:06:29 himinbjorg kernel: ffs_fsync(dbb54ca0) at ffs_fsync+0x33e
> Oct 10 22:06:29 himinbjorg kernel: fsync(c3549600,dbb54d04,1,1,286) at fsync+0x1
> 03
> Oct 10 22:06:29 himinbjorg kernel: syscall(2f,2f,bfbf002f,80fef20,0) at syscall+
> 0x227
> Oct 10 22:06:29 himinbjorg kernel: Xint0x80_syscall() at Xint0x80_syscall+0x1f
> Oct 10 22:06:29 himinbjorg kernel: --- syscall (95, FreeBSD ELF32, fsync), eip =
>  0x28181ca7, esp = 0xbfbf6d1c, ebp = 0xbfbf86e8 ---

This looks more like a filesystem problem, not a memory problem.  All
of the functions listed in the backtrace show UFS/FFS problems and
filesystem metadata issues of some kind.

Booting the machine in single-user mode and run "fsck -y".  I'm betting
you'll find errors.  If not, then it's probably a kernel bug -- see
below, however.

I doubt you're going to get much support on this, since you're running
FreeBSD 5.5, which is no longer supported.  Believe me: you will get
continual push-back from the rest of the FreeBSD developers asking for
support on 5.5.  The RELENG_6 series is on its way out as well, so
you should consider installing RELENG_7 (specifically 7.1-BETA at
this point).

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |