[BUG] Linux 2.6.25-rc2 - Regression from 2.6.24-rc1-git1 softlockup while bootup on powerpc

[Andrew Morton]

On Tue, 19 Feb 2008 09:36:34 +0100 Jens Axboe <jens.axboe at oracle.com> wrote:

> But I think the radix 'scan over entire tree' is a bit fragile.

eek, it had better not be.  Was this an error in the caller?  Hope so.

> This
> patch adds a parallel hlist for ease of properly browsing the members,

Even though io_contexts are fairly uncommon, adding more stuff to a data
structure was a pretty sad alternative to fixing a bug in
radix_tree_gang_lookup(), or to fixing a bug in a caller of it.

IOW: what exactly went wrong here??