From: Arjan van de Ven <arjan@infradead.org>
To: Linus Torvalds <torvalds@osdl.org>
Cc: David Woodhouse <dwmw2@infradead.org>,
Alexandre Oliva <aoliva@redhat.com>,
dhowells <dhowells@redhat.com>, Paul Mackerras <paulus@samba.org>,
Greg KH <greg@kroah.com>, Matthew Wilcox <matthew@wil.cx>,
hch@infradead.org,
Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] Splitting kernel headers and deprecating __KERNEL__
Date: Wed, 01 Dec 2004 09:10:53 +0100 [thread overview]
Message-ID: <1101888653.2640.10.camel@laptop.fenrus.org> (raw)
In-Reply-To: <Pine.LNX.4.58.0411301612370.22796@ppc970.osdl.org>
On Tue, 2004-11-30 at 16:18 -0800, Linus Torvalds wrote:
> On Tue, 30 Nov 2004, Linus Torvalds wrote:
> >
> > Even atomic.h. I could well imagine that somebody includes atomic.h just
> > to get the thread-safe updates for some architectures. For example,
> > asm-alpha/atomic.h does it right, and I would not be at all surprised if
> > somebody had noticed.
>
> In fact, this is not entirely theoretical.
indeed it's not. THere were projects that used the x86 atomic.h
header.... but failed to notice that its not actually using the lock
prefix if you don't define CONFIG_SMP. Now it's purely up to luck if the
userspace headers in /usr/include have CONFIG_SMP defined or not, so
there have been cases where people compiled on an UP box and got racy
code. Was a production level project; normally they built on SMP but
once they built on UP .. poof ;)
so atomic.h is *dangerous* for userspace to use, at least on x86. It
gives a false feeling of atomicity.
So dangerous that for the RH/Fedora distros, we don't ship the
questionable parts of it.
next prev parent reply other threads:[~2004-12-01 8:11 UTC|newest]
Thread overview: 185+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-25 15:13 [RFC] Splitting kernel headers and deprecating __KERNEL__ David Howells
2004-11-25 15:23 ` David Woodhouse
2004-11-25 16:54 ` Matthew Wilcox
2004-11-25 18:17 ` David Woodhouse
2004-11-27 3:24 ` Greg KH
2004-11-28 23:37 ` Paul Mackerras
2004-11-29 1:28 ` Linus Torvalds
2004-11-29 4:36 ` Jeff Garzik
2004-11-29 4:57 ` Al Viro
2004-11-29 5:27 ` Tim Hockin
2004-11-29 7:51 ` Arjan van de Ven
2004-12-05 0:49 ` Rob Landley
2004-12-05 2:26 ` Andries Brouwer
2004-12-05 13:19 ` David Greaves
2004-12-05 15:57 ` Andries Brouwer
2004-12-05 23:05 ` Rob Landley
2004-12-06 9:56 ` Andries Brouwer
2004-11-29 9:42 ` David Woodhouse
2004-11-30 8:08 ` Alex Riesen
2004-11-30 8:57 ` Alex Riesen
2004-12-01 11:46 ` Ralf Baechle
2004-12-02 1:21 ` H. Peter Anvin
2004-11-29 9:53 ` Paul Mackerras
2004-11-29 9:57 ` Arjan van de Ven
2004-11-29 10:01 ` David Woodhouse
2004-11-29 11:41 ` Mariusz Mazur
2004-11-29 17:09 ` Alexandre Oliva
2004-11-29 17:41 ` Linus Torvalds
2004-11-29 22:44 ` Al Viro
2004-12-01 11:36 ` Roman Zippel
[not found] ` <oract0thnj.fsf@livre.redhat.lsd.ic.unicamp.br>
2004-11-29 23:00 ` Linus Torvalds
2004-11-30 0:45 ` H. Peter Anvin
2004-11-30 5:31 ` Herbert Poetzl
2004-11-30 6:44 ` bert hubert
2004-11-30 21:22 ` Alexandre Oliva
2004-11-30 22:22 ` Linus Torvalds
2004-11-30 22:57 ` Alexandre Oliva
2004-11-30 23:12 ` Linus Torvalds
2004-12-01 19:41 ` Alexandre Oliva
2004-12-01 19:54 ` Matthew Wilcox
2004-12-02 3:58 ` Linus Torvalds
2004-12-02 4:28 ` Bernd Eckenfels
2004-12-02 5:11 ` Peter Williams
2004-12-02 11:30 ` Tomas Carnecky
2004-12-02 22:17 ` Peter Williams
2004-12-02 9:29 ` Pekka Enberg
2004-12-02 15:35 ` Linus Torvalds
2004-12-02 21:46 ` Pekka Enberg
2004-11-30 15:35 ` David Woodhouse
2004-11-30 15:58 ` Linus Torvalds
2004-11-30 16:28 ` David Woodhouse
2004-11-30 16:53 ` Linus Torvalds
2004-11-30 17:52 ` David Woodhouse
2004-11-30 18:21 ` Linus Torvalds
2004-11-30 20:28 ` Mariusz Mazur
2004-11-30 20:47 ` Linus Torvalds
2004-11-30 22:33 ` Sam Ravnborg
2004-11-30 22:44 ` Mariusz Mazur
2004-11-30 23:03 ` Al Viro
2004-11-30 23:08 ` Mariusz Mazur
2004-12-01 5:23 ` Sam Ravnborg
2004-12-01 10:52 ` Mariusz Mazur
2004-12-01 18:08 ` Sam Ravnborg
2004-11-30 23:13 ` Alexandre Oliva
2004-11-30 23:36 ` Chris Friesen
2004-12-01 5:50 ` H. Peter Anvin
2004-11-30 22:48 ` Matt Mackall
2004-11-30 22:51 ` Christoph Hellwig
2004-11-30 23:09 ` Chris Friesen
2004-11-30 23:35 ` Matt Mackall
2004-12-01 0:23 ` Miquel van Smoorenburg
2004-11-30 22:55 ` Linus Torvalds
2004-11-30 23:29 ` Matt Mackall
2004-12-03 1:03 ` Krzysztof Halasa
2004-11-30 23:51 ` David Woodhouse
2004-11-30 17:55 ` Al Viro
2004-11-30 16:33 ` David Howells
2004-11-30 16:57 ` Linus Torvalds
2004-11-30 15:33 ` David Howells
2004-11-30 15:51 ` Linus Torvalds
2004-11-30 20:47 ` Alexandre Oliva
2004-11-30 20:56 ` Linus Torvalds
2004-11-30 21:30 ` Alexandre Oliva
2004-11-30 21:39 ` Alexandre Oliva
2004-11-30 23:33 ` Matthew Wilcox
2004-11-30 22:25 ` Linus Torvalds
2004-11-30 22:34 ` David Woodhouse
2004-11-30 22:51 ` Linus Torvalds
2004-11-30 23:50 ` David Woodhouse
2004-12-01 0:10 ` Linus Torvalds
2004-12-01 0:18 ` Linus Torvalds
2004-12-01 8:10 ` Arjan van de Ven [this message]
2004-12-01 0:24 ` David Woodhouse
2004-12-01 0:37 ` Linus Torvalds
2004-12-01 0:47 ` David Woodhouse
2004-12-01 0:57 ` Linus Torvalds
2004-12-01 1:06 ` David Woodhouse
2004-12-01 1:23 ` Linus Torvalds
2004-12-01 6:48 ` BAIN
2004-12-01 2:02 ` cdrom.h (was Re: [RFC] Splitting kernel headers...) Matthew Wilcox
2004-11-30 22:52 ` [RFC] Splitting kernel headers and deprecating __KERNEL__ Mariusz Mazur
2004-11-30 23:05 ` Linus Torvalds
2004-11-30 23:05 ` Alexandre Oliva
2004-11-30 16:18 ` David Howells
2004-12-14 5:51 ` Werner Almesberger
2004-12-14 15:49 ` Linus Torvalds
2004-12-14 16:50 ` Werner Almesberger
2004-12-14 17:58 ` Linus Torvalds
2004-12-14 21:46 ` Werner Almesberger
2004-12-14 21:58 ` Linus Torvalds
2004-12-14 23:49 ` Krzysztof Halasa
2004-12-15 0:09 ` Werner Almesberger
2004-12-16 0:58 ` Krzysztof Halasa
2004-12-14 19:23 ` Horst von Brand
2004-12-14 19:45 ` Sam Ravnborg
2004-12-14 19:58 ` Linus Torvalds
2004-12-14 20:25 ` Andreas Schwab
2004-12-14 20:33 ` Linus Torvalds
2004-12-14 16:55 ` Andreas Schwab
2004-12-14 17:59 ` Linus Torvalds
2004-11-27 20:39 ` Sam Ravnborg
2004-11-25 18:20 ` Alexandre Oliva
2004-11-25 21:01 ` Matthew Wilcox
2004-11-25 22:35 ` David Woodhouse
2004-11-26 11:42 ` Alexandre Oliva
2004-11-27 0:13 ` Andreas Steinmetz
2004-11-27 0:26 ` David Woodhouse
2004-11-27 0:30 ` Andreas Steinmetz
2004-11-27 0:38 ` David Woodhouse
2004-11-26 11:47 ` Alexandre Oliva
2004-11-26 11:53 ` David Woodhouse
2004-11-27 16:12 ` Krzysztof Halasa
2004-11-26 11:58 ` David Howells
2004-11-26 12:00 ` David Woodhouse
2004-11-26 14:19 ` Matthew Wilcox
2004-11-26 14:33 ` David Woodhouse
2004-11-27 12:10 ` Alexander Stohr
2004-11-27 3:46 ` Adam Heath
2004-11-30 12:18 ` Horst von Brand
2004-11-29 16:34 ` Alexandre Oliva
2004-11-25 18:45 ` Matthew Wilcox
2004-11-26 11:52 ` David Howells
2004-11-26 23:56 ` Grzegorz Kulewski
2004-11-27 1:27 ` Tomas Carnecky
2004-11-27 1:41 ` Grzegorz Kulewski
2004-11-27 2:03 ` Tomas Carnecky
2004-11-27 3:07 ` Kyle Moffett
2004-11-27 4:29 ` Tonnerre
2004-11-27 3:51 ` Matthew Wilcox
2004-11-27 16:47 ` Randy.Dunlap
2004-11-27 17:16 ` David Woodhouse
2004-11-27 22:53 ` Arnd Bergmann
2004-11-27 23:12 ` David Woodhouse
2004-11-27 23:27 ` Randy.Dunlap
2004-11-27 23:32 ` David Woodhouse
2004-11-27 23:56 ` Arnd Bergmann
2004-11-28 7:13 ` Arjan van de Ven
2004-11-28 12:03 ` Arnd Bergmann
2004-11-28 12:19 ` Arjan van de Ven
2004-11-28 16:34 ` Kevin Puetz
2004-11-28 12:28 ` Wichert Akkerman
2004-11-28 12:44 ` Arjan van de Ven
2004-11-28 16:21 ` Jakub Jelinek
2004-11-28 7:20 ` Christoph Hellwig
2004-11-27 4:05 ` Chris Friesen
2004-11-27 4:30 ` Tomas Carnecky
2004-11-27 21:03 ` Sam Ravnborg
2004-11-27 21:11 ` Andreas Steinmetz
2004-11-27 21:19 ` Sam Ravnborg
2004-11-27 21:49 ` Andreas Steinmetz
2004-11-27 23:21 ` Arnd Bergmann
2004-11-28 13:24 ` Andreas Steinmetz
2004-11-28 13:40 ` Arnd Bergmann
2004-11-29 11:08 ` David Howells
2004-11-29 20:01 ` H. Peter Anvin
2004-11-30 0:34 ` Kyle Moffett
2004-11-30 0:51 ` H. Peter Anvin
2004-12-14 7:07 ` Werner Almesberger
2004-11-27 19:43 Dan Kegel
2004-11-27 21:06 ` Sam Ravnborg
[not found] <34Xo6-2P0-19@gated-at.bofh.it>
[not found] ` <35i9f-2vZ-25@gated-at.bofh.it>
[not found] ` <35iLS-2Uo-1@gated-at.bofh.it>
[not found] ` <35kb6-46Q-25@gated-at.bofh.it>
2004-11-28 0:55 ` ak
2004-11-28 13:32 ` Arnd Bergmann
2004-11-30 1:43 Jean Tourrilhes
2004-11-30 4:22 ` Linus Torvalds
2004-11-30 6:51 ` H. Peter Anvin
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