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Date: Wed, 1 Nov 2006 12:54:29 -0500
From: Kris Kennaway <kris@obsecurity.org>
To: Ulrich Spoerlein <uspoerlein@gmail.com>
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Cc: stable@freebsd.org, Kris Kennaway <kris@obsecurity.org>
Subject: Re: panic: vfs_getopt: caller passed 'opts' as NULL
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On Wed, Nov 01, 2006 at 11:57:48AM +0100, Ulrich Spoerlein wrote:

> I grepped /sys for DEBUG_VFS_LOCKS and it seems to only add some
> additional KASSERTs, but not the one which triggered in the original
> panic.
>=20
> Nullfs seems more fragile than I initially thought ...

It's just that compiling in the extra debugging (it might be
DEBUG_LOCKS or DEBUG_VFS_LOCKS, I forget which), causes the sizes of
structures to change, so when the module tries to fondle the structure
at a certain offset thinking it's accessing a certain field, it's
really fondling something else entirely and the kernel gets a nasty
surprise and panics.

Kris

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