Using read-only NULLFS leads to panic. gdb output included, easy toreproduce.

Pawel Malachowski pawmal-posting at
Wed Mar 3 04:14:02 PST 2004

On Wed, Mar 03, 2004 at 10:48:16PM -0000, James Read wrote:

> All I can say is that I've had this happen to me before. 'Me too'
> The ports were mounted in exact the same way, but with rw instead of ro.
> Also a few jails were running at the time, infact 3 were. All had /usr/ports
> mount_null'ed inside there jail.

OT, but it is rather bad idea to have rw mounted /usr/ports shared
beetween hosts/jails. Ports tree can be trojaned from one jail and
everything can be compromised this way.

> After running find from the usual periodic scripts it brought the machine
> down every time it ran that script.

True, my setup was runnig successfully for months. The only change I made
few days ago was to start cron inside jails. :)

> If there is a better way / another way to 'mount_null' /usr/ports (or any
> other mount point for that matter) to other places in/on the filesystem, by
> using NFS or other such things, then speak up! I don't like getting panics
> more then anyone else does ;>

I hope this can be fixed inside nullfs. Tjr@ asked about reproducing this
on 5.x -- it was not possible to panic, so a fix may be already in HEAD.
However, second problem (every process stalls after trying do play with
filesystem) was exposed, see other posts in this thread.

Paweł Małachowski

More information about the freebsd-stable mailing list