From: "Dmitry V. Levin" <ldv@altlinux.org>
To: Carlos O'Donell <carlos@redhat.com>
Cc: libc-alpha@sourceware.org
Subject: Re: synchronizing kernel UAPI and libc headers
Date: Sun, 23 Apr 2017 00:35:00 -0000 [thread overview]
Message-ID: <20170423003520.GB19409@altlinux.org> (raw)
In-Reply-To: <db092be8-bf50-521c-f83a-774f23f20b67@redhat.com>
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On Fri, Apr 21, 2017 at 11:16:26AM -0400, Carlos O'Donell wrote:
> My opinion is that the upstream kernel UAPI headers continue to change
> without good management of the changes. I have seen at least 3 changes
> which break header inclusion ordering and that would have caused application
> build problems. None of the authors of those changes came to talk to us
> about adding the right guards in glibc to prevent breakage. Worse there
> have been discussions about deleting existing guards, that change would
> break header inclusion order in one of the two directions, just to
> simplify libc-compat.h in the kernel (avoiding needing any libc-specific
> knowledge). This does not seem conservative enough to me.
Unfortunately, there seems to be no good working synchronization mechanism
proposed yet. The procedure described in
https://sourceware.org/glibc/wiki/Synchronizing_Headers has severe
problems on the kernel side. Even with headers that were synchronized
several years ago we have unsolved inclusion issues like this:
$ gcc -xc -c -o/dev/null - <<EOF
#include <linux/in.h>
#include <netinet/in.h>
#include <linux/in6.h>
EOF
or this:
$ gcc -xc -c -o/dev/null - <<EOF
#include <linux/xattr.h>
#include <netinet/in.h>
#include <linux/in6.h>
EOF
See also https://sourceware.org/ml/libc-alpha/2017-04/msg00157.html
It's hard to expect that kernel folks would be adding new guards
if already added guards are so fragile.
--
ldv
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prev parent reply other threads:[~2017-04-23 0:35 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 19:40 [PATCH] <bits/syscall.h>: Use an arch-independent system call list on Linux Florian Weimer
2017-04-06 8:00 ` Andreas Schwab
2017-04-06 8:52 ` Florian Weimer
2017-04-06 9:03 ` Andreas Schwab
2017-04-06 9:47 ` Florian Weimer
2017-04-06 10:07 ` Andreas Schwab
2017-04-06 10:12 ` Florian Weimer
2017-04-06 12:29 ` Andreas Schwab
2017-04-06 12:32 ` Florian Weimer
2017-04-06 12:49 ` Andreas Schwab
2017-04-06 13:24 ` Florian Weimer
2017-04-06 13:44 ` Andreas Schwab
2017-04-06 14:22 ` Florian Weimer
2017-04-06 14:37 ` Dmitry V. Levin
2017-04-21 10:06 ` Florian Weimer
2017-04-21 12:27 ` Andreas Schwab
2017-04-21 12:37 ` Florian Weimer
2017-04-21 18:31 ` Carlos O'Donell
2017-04-21 18:02 ` Andreas Schwab
2017-04-21 18:46 ` Florian Weimer
2017-04-21 19:08 ` Andreas Schwab
2017-04-21 19:15 ` Florian Weimer
2017-04-21 19:34 ` Andreas Schwab
2017-04-21 19:37 ` Florian Weimer
2017-04-21 19:40 ` Andreas Schwab
2017-04-21 19:57 ` Florian Weimer
2017-04-22 9:38 ` Andreas Schwab
2017-04-22 11:59 ` Florian Weimer
2017-04-22 13:45 ` Andreas Schwab
2017-04-22 14:22 ` Florian Weimer
2017-04-22 15:08 ` Andreas Schwab
2017-04-22 15:27 ` Florian Weimer
2017-04-22 15:37 ` Andreas Schwab
2017-04-22 15:51 ` Florian Weimer
2017-04-22 17:27 ` Andreas Schwab
2017-08-24 14:35 ` Carlos O'Donell
2017-08-24 15:15 ` Joseph Myers
2017-08-24 16:08 ` Carlos O'Donell
2017-08-24 18:49 ` Florian Weimer
2017-08-24 20:28 ` Joseph Myers
2017-08-25 14:30 ` Florian Weimer
2017-08-25 15:40 ` Joseph Myers
2017-08-25 15:57 ` Florian Weimer
2017-08-28 11:36 ` Joseph Myers
2017-08-28 12:35 ` Florian Weimer
2017-08-28 12:43 ` Joseph Myers
2017-04-23 0:35 ` Dmitry V. Levin [this message]
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