Re: [autofs] [PATCH 04/38] autofs4: Save autofs trigger's vfsmountin super block info

[Ian Kent]

On Wed, 2010-06-23 at 11:07 +0900, J. R. Okajima wrote:
> Ian Kent:
> > I may be missing something about this, but why is it safe to use
> > iterate_mounts(), since it doesn't take the vfsmount_lock when
> > traversing the list of mounts?
> 
> The sample code was not correct.
> We need to acquire vfsmount_lock or down_read(namespace_sem).

This is looking more and more suspect the more I dig.

The only place iterate_mounts() is called is within the audit subsystem
AFAICS, and I don't see where vfsmount_lock is taken in that code. OTOH,
in fs/namespace.c it is pretty clear that vfsmount->mnt_list is
protected by the vfsmount_lock.

Ummm ... that's gota be broken but maybe someone can give a reason why
it isn't?

Ian


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