From: David Laight <David.Laight@ACULAB.COM>
To: 'Daniel Micay' <danielmicay@gmail.com>,
Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Andreas Christoforou <andreaschristofo@gmail.com>,
Kees Cook <keescook@chromium.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
QCA ath9k Development <ath9k-devel@qca.qualcomm.com>,
Kalle Valo <kvalo@codeaurora.org>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
Netdev <netdev@vger.kernel.org>,
kernel list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] drivers: net: wireless: ath: ath9: dfs: remove VLA usage
Date: Tue, 13 Mar 2018 12:32:17 +0000 [thread overview]
Message-ID: <423b529d48c54eba9f7ed51922814d46@AcuMS.aculab.com> (raw)
In-Reply-To: <CA+DvKQ+hbMoWJdOuQB5n+eVF4ePf=kVuRiMbdtTUZ8ars4Pz4A@mail.gmail.com>
From: Daniel Micay
> Sent: 10 March 2018 23:45
>
> > Just wondering. Is this actually a VLA. FFT_NUM_SAMPLES was static const so
> > not really going to show a lot of variation. This array will always have the
> > same size on the stack.
>
> The issue is that unlike in C++, a `static const` can't be used in a
> constant expression in C. It's unclear why C is defined that way but
> it's how it is and there isn't currently a GCC extension making more
> things into constant expressions like C++.
'static' and 'const' are both just qualifiers to a 'variable'
You can still take it's address.
The language allows you to cast away the 'const' and write to
the variable - the effect is probably 'implementation defined'.
It is probably required to be valid for 'static const' items
to be patchable.
David
next prev parent reply other threads:[~2018-03-13 12:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-09 12:30 [PATCH] drivers: net: wireless: ath: ath9: dfs: remove VLA usage Andreas Christoforou
2018-03-09 12:51 ` Himanshu Jha
2018-03-09 14:48 ` Kalle Valo
2018-03-10 23:06 ` Arend van Spriel
2018-03-10 23:12 ` Kees Cook
2018-03-10 23:26 ` Gustavo A. R. Silva
[not found] ` <CAGXu5jKDA=L5E6Cu_oRe-M=ouuhrccCZHyM+z6_UMAUqe9xnRQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-03-14 1:38 ` Miguel Ojeda
2018-03-10 23:44 ` Daniel Micay
2018-03-13 12:32 ` David Laight [this message]
2018-03-14 1:18 ` Daniel Micay
2018-03-14 1:22 ` Daniel Micay
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