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Date:   Fri, 23 Dec 2022 15:03:12 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Lorenzo Stoakes <lstoakes@gmail.com>
Cc:     Christoph Hellwig <hch@lst.de>, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
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Subject: Re: [PATCH 2/2] vmalloc: reject vmap with VM_FLUSH_RESET_PERMS
Message-ID: <20221223140312.GA26826@lst.de>
References: <20221223092703.61927-1-hch@lst.de> <20221223092703.61927-3-hch@lst.de> <Y6WB2ZGoL7FaFK+f@lucifer>
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On Fri, Dec 23, 2022 at 10:24:25AM +0000, Lorenzo Stoakes wrote:
> Might it be worth adding a specific vmap mask that explicitly indicates what
> flags are permissible on vmap()? Then this could become e.g.:-
> 
> 	if (WARN_ON_ONCE(flags & ~VM_VMAP_PERMITTED_MASK))
> 		return NULL;
> 
> And would be self-documenting as to why we are disallowing flags (i.e. they are
> not part of the permitted vmap mask).

That's probably a good idea.  It might need some time to audit
for use of all the flags, though.