Subject: Re: ffs panic with 1.5C (19/11/2000)
To: Anders Magnusson <ragge@ludd.luth.se>
From: Frank van der Linden <fvdl@wasabisystems.com>
List: tech-kern
Date: 11/03/2000 16:43:44
On Thu, Nov 02, 2000 at 12:53:32PM +0100, Anders Magnusson wrote:
> The vgonel panic happens very often on a production machine we have here.
> Is there anyone that knows more about this area of the kernel that can
> give me some hints about what to search for?

This panic appears to be the same one as in PRs 11193 and 11416. Since
it's also present on the 1.5 branch. it's a serious problem.

What seems to happen here is that some vnode is put on the freelist
in a bad state (at least, with a lock that's messed up). At some
point, a filesystem comes along needing a new one, getnewvnode()
calls vgonel() on it to flush it out and prepare it for reuse, and
bang, it panics.

The thing to do is to collect as much information as possible
about the bad vnode, most importantly which filesystem it belonged
to previously.

- Frank