mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: "Michael J. Baars" <mjbaars1977.gcc@cyberfiber.eu>
To: Andrew Pinski <pinskia@gmail.com>
Cc: GCC Mailing List <gcc@gcc.gnu.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: problems with memory allocation and the alignment check
Date: Mon, 22 Feb 2021 10:37:33 +0100	[thread overview]
Message-ID: <d9a2cdcf116ed32874ed02bd6fa60ad899ce5f50.camel@cyberfiber.eu> (raw)
In-Reply-To: <CA+=Sn1njFZ-XZRHJdmjzOyvXvcMXg+oBao=wK8w3RXN_Ji=fLA@mail.gmail.com>

On Mon, 2021-02-22 at 01:29 -0800, Andrew Pinski wrote:
> On Mon, Feb 22, 2021 at 1:17 AM Michael J. Baars
> <mjbaars1977.gcc@cyberfiber.eu> wrote:
> > Hi,
> > 
> > I just wrote this little program to demonstrate a possible flaw in both malloc and calloc.
> > 
> > If I allocate a the simplest memory region from main(), one out of three optimization flags fail.
> > If I allocate the same region from a function, three out of three optimization flags fail.
> > 
> > Does someone know if this really is a flaw, and if so, is it a gcc or a kernel flaw?
> 
> There is no flaw.  GCC (kernel, glibc) all assume unaligned accesses
> on x86 will not cause an exception.

Is this just an assumption or more like a fact? I agree with you that byte aligned is more or less the same as unaligned.

> 
> Thanks,
> Andrew
> 
> > Regards,
> > Mischa.


  reply	other threads:[~2021-02-22 10:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22  9:08 Michael J. Baars
2021-02-22  9:29 ` Andrew Pinski
2021-02-22  9:37   ` Michael J. Baars [this message]
2021-02-22  9:41     ` Andrew Pinski
2021-02-22 10:04       ` Michael J. Baars
2021-02-24  7:05       ` Michael J. Baars
2021-02-23 11:46     ` David Laight

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=d9a2cdcf116ed32874ed02bd6fa60ad899ce5f50.camel@cyberfiber.eu \
    --to=mjbaars1977.gcc@cyberfiber.eu \
    --cc=gcc@gcc.gnu.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pinskia@gmail.com \
    /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
all inboxes | Powered by JetHome®