From: Joseph Myers <joseph@codesourcery.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Carlos O'Donell <carlos@redhat.com>,
Florian Weimer <fw@deneb.enyo.de>,
"Tsimbalist, Igor V" <igor.v.tsimbalist@intel.com>,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH] x86: Use pad in pthread_unwind_buf to preserve shadow stack register
Date: Tue, 17 Apr 2018 20:03:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1804171959590.1402@digraph.polyomino.org.uk> (raw)
In-Reply-To: <CAMe9rOr68P6Z=rX=xeFG1PbQE1fZ14iN3NmZEpChjP6QmUfS8g@mail.gmail.com>
On Fri, 6 Apr 2018, H.J. Lu wrote:
> https://github.com/hjl-tools/glibc/commit/9bf6aefa8fb45f8df140d42ce9cf890bb24076e1
>
> It should be binary backward compatible. I will investigate if there is a way
Increasing the size of a public type is always dangerous, because you can
end up with one part of a program expecting the new, larger size but
another part only allocating the old, smaller size.
It might in some cases be compatible to the extent that existing linked
programs and shared libraries work with new glibc, if new glibc will never
try to write into the unallocated part of such objects allocated by an
existing linked program or shared library. However, any such change would
need a careful analysis of how the type gets written to, and to what
extent external libraries have interfaces that depend on the size of the
type, and would need a NEWS entry explaining the change and discussing the
compatibility issues with it.
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2018-04-17 20:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-30 17:41 H.J. Lu
2018-04-06 4:46 ` Carlos O'Donell
2018-04-06 12:59 ` H.J. Lu
2018-04-06 20:26 ` H.J. Lu
2018-04-12 21:36 ` Carlos O'Donell
2018-04-12 21:36 ` Carlos O'Donell
2018-04-12 23:50 ` H.J. Lu
2018-04-21 3:28 ` [PATCHv2] " Carlos O'Donell
2018-04-21 18:37 ` [PATCH/v3] " H.J. Lu
2018-05-02 4:43 ` Carlos O'Donell
2018-05-02 12:45 ` H.J. Lu
2018-04-17 20:03 ` Joseph Myers [this message]
2018-04-17 23:20 ` [PATCH] " H.J. Lu
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=alpine.DEB.2.20.1804171959590.1402@digraph.polyomino.org.uk \
--to=joseph@codesourcery.com \
--cc=carlos@redhat.com \
--cc=fw@deneb.enyo.de \
--cc=hjl.tools@gmail.com \
--cc=igor.v.tsimbalist@intel.com \
--cc=libc-alpha@sourceware.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 read-only IMAP folder(s) and NNTP newsgroup(s).