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From: Andy Lutomirski <luto@amacapital.net>
Date: Wed, 8 Mar 2017 10:54:07 -0800
Message-ID: <CALCETrVDzaZ_eCsXs3Jj+ZDUOPGHKVAKJdzPnZkdfHtUF8aKhQ@mail.gmail.com>
Subject: Re: v4.10: kernel stack frame pointer .. has bad value (null)
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>, Pavel Machek <pavel@ucw.cz>,
        kernel list <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>, Andrew Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
        Denys Vlasenko <dvlasenk@redhat.com>, Peter Anvin <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>
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On Wed, Mar 8, 2017 at 10:25 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Wed, Mar 8, 2017 at 9:37 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> Yeah. At some point we might even upgrade the compiler requirements to
> no longer accept the mcount model.
>
> I think the fentry model is gcc-4.6.0 and up. Currently I guess we
> support gcc-3.2+, which is fairly ridiculous considering that 4.6.0 is
> from March, 2011. So it's over five years ago already.
>
> gcc-3.2.0 is from 2002, I think. At some point you just have to say
> "caring about a 15 year old compiler is ridiculous"
>
> The main reason we have fairly aggressively supported old compilers
> tends to be some odder architectures that don't have good support, so
> people use various random "this works for me" versions.

I thought it was because akpm still used Fedora Core 6. :)

At some point, it would be nice to skip way forward and require a
compiler without the 16-byte-stack-alignment bug, too.

--Andy