Root FS corruption

[Yar Tikhiy]

On Thu, May 18, 2006 at 08:19:17PM +0200, Thomas-Martin Seck wrote:
> * Yar Tikhiy <yar at comp.chem.msu.su>:
> 
> > I saw the following / corruption in a fresh CURRENT when using
> > nextboot.  Of course, it wasn't the fault of nextboot itself,
> > nextboot simply was the only utility to modify / in my case.
> > 
> > I found the contents of nextboot.conf once in my custom /root/supfile,
> > the other time in the stock /etc/protocols.  /etc/protocols was
> > large enough to see how the corruption had happened: the first
> > fragment, 2048 bytes, of the file was replaced by the contents of
> > nextboot.conf, zero padded.
> >
> > The / was a usual 2048/16384 UFS2 without soft-updates.  The kernel
> > was GENERIC.  Forced fsck reported no problems at all.  The / had
> > never been dirty because I used nextboot to boot single-user with
> > all FSen read-only and investigate a panic unrelated to FS.
> > 
> > Did any one see a similar problem of fragment mis-allocation?
> 
> I experienced the exact same corruption some months ago with a RELENG_6
> test system I update regularly. Unfortunately, this corruption happened
> only once, I was never able to reproduce it since.
> 
> The kernel is a stripped down GENERIC, /root is a 2048/16384 UFS2 fs.

Thank you for your reply!  Apropos, today /boot/kernel/ng_fec.ko
fell a victim to the corruption in exactly the same way: its first
fragment was replaced by the nextboot.conf contents.  The system
was updated last time on the day before yesterday.

Of course, more / corruption is likely.  The case of nextboot.conf
is just detectable easily.  Thank Daemon, it's a test machine and
not a production server.  I'm still trying to find a pattern in the
corruption.

-- 
Yar