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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 2 Nov 2016 09:02:06 -0600
Message-ID: <CA+55aFxbUd6kZH0ugn-Ss5CqE=MttGD=WChzahAp1k-XFcr7xA@mail.gmail.com>
Subject: Re: [PATCH 01/12] extarray: define helpers for arrays defined in
 linker scripts
To: Richard Biener <rguenther@suse.de>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>,
        Peter Zijlstra <peterz@infradead.org>,
        "Luis R. Rodriguez" <mcgrof@kernel.org>,
        Vegard Nossum <vegard.nossum@oracle.com>, Jiri Slaby <jslaby@suse.cz>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable <stable@vger.kernel.org>, Ming Lei <ming.lei@canonical.com>,
        Steven Rostedt <srostedt@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Cesar Eduardo Barros <cesarb@cesarb.eti.br>,
        Michael Matz <matz@suse.de>, David Miller <davem@davemloft.net>,
        Guenter Roeck <linux@roeck-us.net>,
        Fengguang Wu <fengguang.wu@intel.com>, Borislav Petkov <bp@alien8.de>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>, Kees Cook <keescook@chromium.org>
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On Wed, Nov 2, 2016 at 6:14 AM, Richard Biener <rguenther@suse.de> wrote:
>
> Note while this change restored the old behavior this change was _not_
> intended to fix this particular fallout (it was to fix an inconsistency
> with respect to comparing addresses of symbols that can be interposed).
> It just happens that your externs can be interposed with ELF.

I think it should in general work for the kernel too, since as far as
I can tell, it fundamentally fixes the issue that linker scripts will
set symbol addresses to possibly alias other symbols.

So from a compiler standpoint, I think our "begin/end" linker script
symbols can be seen as interposing a larger array and give bounds for
it. No>

                  Linus