Oddities in dmesg

[Jeremy Chadwick]

On Wed, Jan 13, 2010 at 11:44:15AM -0500, Boris Kochergin wrote:
> Christoffer Persson wrote:
> >I've recently rebooted one of our servers running FreeBSD 7.2-RELEASE-p4. I found this oddity in the boot message:
> >
> >GEOM_LABEL: Label for provider da0s1a is ufsid/48b6d1673e4caa72.
> >GEOM_LABEL: Label ufsid/48b6d1673e4caa72 removed.
> >
> >GEOM_WLAARBNEILN:G : L/atbmepl  wuafss indo/t4 8pbr6odp1e6r7lay3 addi0s1m3odu nrteemdov
> >ed.
> >
> >GEOM_LABEL: Label ufsid/48b6d167a8e1f985 removed.
> >WARNING: /usr was not properly dismounted
> >
> >
> >Just repeated once, looks like it's a garble between two lines in the boot message. Has anyone seen this happening before
> >or any idea what made it happen?
> >
> >/Christoffer Persson
>
> Yeah, this is due to lack of synchronization between multiple pieces
> of code wanting to print something in parallel. I don't know if
> anything can be done about it in 7.x, but the "PRINTF_BUFR_SIZE=128"
> option in the GENERIC kernel for 8.x takes care of it.

This isn't quite true -- use of the option (increasing the buffer size)
appears to decrease the chance and/or severity of the interspersed
output, but it still happens.  This applies to both 7.x and 8.x.

I'll note that I've seen Solaris 10 and (occasionally) Linux do this as
well.

-- 
| 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 |