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Date:   Thu, 1 Aug 2019 17:09:10 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Ondrej Mosnacek <omosnace@redhat.com>
Cc:     selinux@vger.kernel.org, Paul Moore <paul@paul-moore.com>,
        linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v2 0/4] selinux: fix race when removing selinuxfs entries
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References: <20190801140243.24080-1-omosnace@redhat.com>
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On Thu, Aug 01, 2019 at 04:02:39PM +0200, Ondrej Mosnacek wrote:
> After hours and hours of getting familiar with dcache and debugging,
> I think I finally found a solution that works and hopefully stands a
> chance of being committed.
> 
> The series still doesn't address the lack of atomicity of the policy
> reload transition, but this is part of a wider problem and can be
> resolved later. Let's fix at least the userspace-triggered lockup
> first.

I don't think this is the right approach.  Consider the related problem:
what happens if somebody has mounted something upon a selinuxfs file?
That is the hard part here, and AFAICS your variant doesn't help it
at all...