BUG: spinlock recursion (sys_chdir, user_path_at, do_path_lookup ...)

[Thomas Gleixner]

On Wed, 12 Jan 2011, Uwe Kleine-König wrote:
> > Reverting: fs: rcu-walk aware d_revalidate method
> > commit: 34286d6662308d82aed891852d04c7c3a2649b16
> I found that one, too, in the meantime.  Currently debugging that with
> tglx on irc.

The last finding is that parent and dentry in
nameidata_dentry_drop_rcu() are the same, which explains the lock
recursion nicely. 

@nick: Anything you want us to add to the debugging ?

@peterz: Why does lockdep ignore the lock recursion in that
	 spin_lock_nested() call?

Thanks,

	tglx