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Date:   Thu, 24 Jan 2019 10:22:28 -0800
From:   Eric Biggers <ebiggers@kernel.org>
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "Jason A . Donenfeld" <Jason@zx2c4.com>
Subject: Re: [RFC/RFT PATCH 00/15] crypto: improved skcipher, aead, and hash
 tests
Message-ID: <20190124182226.GA10448@gmail.com>
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On Thu, Jan 24, 2019 at 05:23:59PM +0800, Herbert Xu wrote:
> On Thu, Jan 24, 2019 at 09:50:35AM +0100, Ard Biesheuvel wrote:
> >
> > Thanks for yet another round of cleanup
> > 
> > I'll look into these, but I'd like to clarify one thing first.
> > 
> > IIUC, you are trying to deal with the case where a single scatterlist
> > element describes a range that strides two pages, and I wonder if that
> > is a valid use of scatterlists in the first place.
> > 
> > Herbert?
> 
> Yes it is valid.  IIRC the network stack may generate such a
> scatterlist.
> 

Also it can easily happen with kmalloced buffers, e.g.

	buf = kmalloc(10000, GFP_KERNEL);

	[...]

	sg_init_one(&sg, buf, 10000);

- Eric