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Date:   Sat, 28 Nov 2020 05:23:17 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Walt Drummond <walt@drummond.us>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org,
        hpa@zytor.com, brgerst@gmail.com, linux@dominikbrodowski.net,
        gustavoars@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/signals: Fix save/restore signal stack to correctly
 support sigset_t
Message-ID: <20201128052317.GY3576660@ZenIV.linux.org.uk>
References: <20201119221132.1515696-1-walt@drummond.us>
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On Thu, Nov 19, 2020 at 02:11:33PM -0800, Walt Drummond wrote:
> The macro unsafe_put_sigmask() only handles the first 64 bits of the
> sigmask_t, which works today.  However, if the definition of the
> sigset_t structure ever changed,

... existing userland would get fucked over, since sigset_t is
present in user-visible data structures.  Including the ones
we are using that thing for - struct rt_sigframe, for starters.

Layout of those suckers is very much cast in stone.  We *can't*
change it, no matter what we do kernel-side.

NAKed-by: Al Viro <viro@zeniv.linux.org.uk>