Re: [patch 01/28] fs: d_validate fixes

From: Andi Kleen
Date: Wed Nov 17 2010 - 05:44:23 EST


Nick Piggin <npiggin@xxxxxxxxx> writes:

> d_validate has been broken for a long time.
>
> kmem_ptr_validate does not guarantee that a pointer can be dereferenced
> if it can go away at any time. Even rcu_read_lock doesn't help, because
> the pointer might be queued in RCU callbacks but not executed yet.

I wonder if that is a problem for NFS ... (which I believe is the only
user). Could these races be used to break the NFS server?

-Andi
--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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