From: Daniel Micay <danielmicay@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>, Joern Engel <joern@logfs.org>,
"Tobin C. Harding" <tobin@apporbit.com>,
"Tobin C. Harding" <me@tobin.cc>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Tycho Andersen <tycho@tycho.ws>,
Oleg Drokin <oleg.drokin@intel.com>,
Andreas Dilger <andreas.dilger@intel.com>,
James Simmons <jsimmons@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
"Gustavo A. R. Silva" <garsilva@embeddedor.com>
Subject: Re: VLA removal (was Re: [RFC 2/2] lustre: use VLA_SAFE)
Date: Thu, 8 Mar 2018 00:05:27 -0500 [thread overview]
Message-ID: <CA+DvKQ+bZauBVA9G-E74ibRuDyfiZfduwycVwBH3jKDyjDe4Zg@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com>
On 7 March 2018 at 13:09, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Wed, Mar 7, 2018 at 9:37 AM, Kees Cook <keescook@chromium.org> wrote:
>>
>> Building with -Wvla, I see 209 unique locations reported in 60 directories:
>> http://paste.ubuntu.com/p/srQxwPQS9s/
>
> Ok, that's not so bad. Maybe Greg could even add it to one of those
> things he encourages new people to do?
>
> Because at least *some* of them are pretty trivial. For example,
> looking at the core code, I was surprised to see something in
> lib/btree.c
Some are probably just the issue of technically having a VLA that's
not really a VLA:
static const int size = 5;
void foo(void) {
int x[size];
}
% gcc -c -Wvla foo.c
foo.c: In function ‘foo’:
foo.c:4:3: warning: ISO C90 forbids variable length array ‘x’ [-Wvla]
int x[size];
^~~
I don't really understand why the C standard didn't make `static
const` declarations usable as constant expressions like C++. They made
the pointer conversions more painful too.
It would be nice to get rid of those cases to use -Werror=vla though.
next prev parent reply other threads:[~2018-03-08 5:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-07 17:37 VLA removal (was Re: [RFC 2/2] lustre: use VLA_SAFE) Kees Cook
2018-03-07 18:09 ` Linus Torvalds
2018-03-08 5:05 ` Daniel Micay [this message]
2018-03-13 21:10 ` [PATCH] btree: avoid variable-length allocations Jörn Engel
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