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Date:   Thu, 24 Mar 2022 21:32:56 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Axel Rasmussen <axelrasmussen@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@kernel.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] mm/secretmem: fix panic when growing a memfd_secret
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On Thu, Mar 24, 2022 at 02:09:09PM -0700, Axel Rasmussen wrote:
> This patch avoids the panic by implementing a custom setattr for
> memfd_secret, which detects resizes specifically (setting the size for
> the first time works just fine, since there are no existing pages to try
> to zero), and rejects them as not supported (ENOTSUP).

Isn't ENOTTY the normal return value for this?  Or even ENOSYS?