From: Jonathan Corbet <corbet@lwn.net>
To: Len Baker <len.baker@gmx.com>, Kees Cook <keescook@chromium.org>
Cc: Len Baker <len.baker@gmx.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Joe Perches <joe@perches.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] docs: deprecated.rst: Clarify open-coded arithmetic with literals
Date: Tue, 14 Sep 2021 15:07:00 -0600 [thread overview]
Message-ID: <87r1dqdfyj.fsf@meer.lwn.net> (raw)
In-Reply-To: <20210829144716.2931-1-len.baker@gmx.com>
Len Baker <len.baker@gmx.com> writes:
> Although using literals for size calculation in allocator arguments may
> be harmless due to compiler warnings in case of overflows, it is better
> to refactor the code to avoid the use of open-coded math idiom.
>
> So, clarify the preferred way in these cases.
>
> Suggested-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Len Baker <len.baker@gmx.com>
> ---
> Changelog v1 -> v2
> - Clarify the sentence by changing "keep <foo> out" with "avoid <foo>"
> (Joe Perches).
>
> Documentation/process/deprecated.rst | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst
> index 9d83b8db8874..b5a8be914178 100644
> --- a/Documentation/process/deprecated.rst
> +++ b/Documentation/process/deprecated.rst
> @@ -60,7 +60,8 @@ smaller allocation being made than the caller was expecting. Using those
> allocations could lead to linear overflows of heap memory and other
> misbehaviors. (One exception to this is literal values where the compiler
> can warn if they might overflow. Though using literals for arguments as
> -suggested below is also harmless.)
> +suggested below is also harmless. So, the preferred way in these cases is
> +to refactor the code to avoid the open-coded math idiom.)
Sorry for being so slow to get to this... honestly, though, I've been
staring at it for a bit and cannot figure out what you are trying to
communicate. What does "math idiom" mean here? If you are trying to
say that using literals is *not* harmless, then perhaps the first part
of the parenthetical should be taken out?
Confused...
jon
next prev parent reply other threads:[~2021-09-14 21:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-29 14:47 [PATCH v2] docs: deprecated.rst: Clarify open-coded arithmetic with literals Len Baker
2021-09-14 21:07 ` Jonathan Corbet [this message]
2021-09-18 9:10 ` Len Baker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87r1dqdfyj.fsf@meer.lwn.net \
--to=corbet@lwn.net \
--cc=gustavoars@kernel.org \
--cc=joe@perches.com \
--cc=keescook@chromium.org \
--cc=len.baker@gmx.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).