From: "Dmitry V. Levin" <ldv@altlinux.org>
To: ALT Devel discussion list <devel@lists.altlinux.org>
Subject: Re: [devel] [PATCH for apt 2/2 v2] Fix pointer arithmetics
Date: Mon, 9 Dec 2019 01:56:20 +0300
Message-ID: <20191208225620.GB30742@altlinux.org> (raw)
In-Reply-To: <20191207175201.13ca3df6c2cfb01ef559b083@altlinux.org>
[-- Attachment #1: Type: text/plain, Size: 912 bytes --]
On Sat, Dec 07, 2019 at 05:52:01PM +0300, Andrey Savchenko wrote:
> Hi all!
>
> On Fri, 6 Dec 2019 18:36:55 +0300 Aleksei Nikiforov wrote:
> > This change should fix pointer arithmetic issues for e2k.
>
> This commit message is misleading. Pointer arithmetic is broken on
> all architectures, but by pure chance in happens to work correctly
> when gcc is used. On e2k the lcc compiler is used, so problem
> manifests itself. But this doesn't change the fact that pointer
> arithmetic was flawed on all architectures.
Strictly speaking, it's not "broken", it's "UB", but I agree
it is not specific to e2k.
My original commit message for this change was the following:
"Fix UB in pointer arithmetic
Commit 6d5e6a689d07de8feef2cbecb24bc42d5994861b aka 0.5.15lorg2-alt70~9
among other changes introduced UB in pointer arithmetic by casting raw
pointers to specific types."
--
ldv
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 801 bytes --]
next prev parent reply other threads:[~2019-12-08 22:56 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-06 13:16 [devel] [PATCH for apt 1/2] Add option for debugging DynamicMMap::Allocate Aleksei Nikiforov
2019-12-06 13:16 ` [devel] [PATCH for apt 2/2] Fix pointer arithmetics Aleksei Nikiforov
2019-12-06 13:36 ` Ivan A. Melnikov
2019-12-06 15:32 ` Aleksei Nikiforov
2019-12-06 15:36 ` [devel] [PATCH for apt 2/2 v2] " Aleksei Nikiforov
2019-12-07 14:52 ` Andrey Savchenko
2019-12-08 22:56 ` Dmitry V. Levin [this message]
2019-12-09 6:54 ` Aleksei Nikiforov
2019-12-12 19:20 ` Andrey Savchenko
2019-12-13 7:58 ` Aleksei Nikiforov
2019-12-08 23:21 ` Dmitry V. Levin
2019-12-09 7:08 ` Aleksei Nikiforov
2019-12-10 0:07 ` Dmitry V. Levin
2019-12-10 8:18 ` Aleksei Nikiforov
2019-12-10 10:20 ` Dmitry V. Levin
2019-12-10 10:58 ` Aleksei Nikiforov
2019-12-10 22:20 ` Dmitry V. Levin
2019-12-11 7:50 ` Aleksei Nikiforov
2019-12-12 19:43 ` Andrey Savchenko
2019-12-13 8:01 ` Aleksei Nikiforov
2019-12-08 23:31 ` [devel] [PATCH for apt 2/2] " Dmitry V. Levin
2019-12-09 7:09 ` Aleksei Nikiforov
2019-12-09 7:16 ` [devel] [PATCH for apt 2/2 v3] " Aleksei Nikiforov
2019-12-09 23:54 ` [devel] [PATCH apt 0/3] Fix 0.5.15lorg2-alt70~9 fallout Dmitry V. Levin
2019-12-09 23:56 ` [devel] [PATCH apt 1/3] apt-pkg/cacheiterators.h: revert #include <set> Dmitry V. Levin
2019-12-09 23:56 ` [devel] [PATCH apt 2/3] apt-pkg/contrib/mmap.cc: revert confusing change of Flags to this->Flags Dmitry V. Levin
2019-12-09 23:56 ` [devel] [PATCH apt 3/3] Fix UB in pointer arithmetic Dmitry V. Levin
2019-12-10 8:18 ` Aleksei Nikiforov
2019-12-08 22:50 ` [devel] [PATCH for apt 1/2] Add option for debugging DynamicMMap::Allocate Dmitry V. Levin
2019-12-09 6:58 ` Aleksei Nikiforov
2019-12-09 10:24 ` Dmitry V. Levin
2019-12-09 11:03 ` [devel] [PATCH for apt 1/2 v3] Add Debug::DynamicMMap::Allocate option Aleksei Nikiforov
2019-12-09 22:59 ` Dmitry V. Levin
2019-12-09 7:00 ` [devel] [PATCH for apt 1/2 v2] Add option for debugging Debug::DynamicMMap::Allocate Aleksei Nikiforov
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=20191208225620.GB30742@altlinux.org \
--to=ldv@altlinux.org \
--cc=devel@lists.altlinux.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
ALT Linux Team development discussions
This inbox may be cloned and mirrored by anyone:
git clone --mirror http://lore.altlinux.org/devel/0 devel/git/0.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 devel devel/ http://lore.altlinux.org/devel \
devel@altlinux.org devel@altlinux.ru devel@lists.altlinux.org devel@lists.altlinux.ru devel@linux.iplabs.ru mandrake-russian@linuxteam.iplabs.ru sisyphus@linuxteam.iplabs.ru
public-inbox-index devel
Example config snippet for mirrors.
Newsgroup available over NNTP:
nntp://lore.altlinux.org/org.altlinux.lists.devel
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git