linux-kernel - Re: [PATCH 6/8] tools/nolibc: tests: add test for -fstack-protector

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Date:   Sun, 26 Mar 2023 21:42:29 +0200
From:   Willy Tarreau <w@....eu>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     Thomas Weißschuh <thomas@...ch.de>,
        Thomas Weißschuh <linux@...ssschuh.net>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/8] tools/nolibc: tests: add test for -fstack-protector

On Sun, Mar 26, 2023 at 10:38:39PM +0300, Alexey Dobriyan wrote:
> > I'm not seeing any issue with your approach instead, let's
> > keep it as-is for now (also it does what the stack protector is supposed
> > to catch anyway).
> 
> There are no guarantess about stack layout and dead writes.
> The test doesn't corrupt stack reliably, just 99.99% reliably.

Sure but it's for a regtest which can easily be adjusted and its
posrtability and ease of maintenance outweights its reliability,
especially when in practice what the code does is what we want to
test for. And if an extra zero needs to be added to the loop, it
can be at a lower cost than maintaining arch-specific asm code.

Willy