From: "Bart Van Assche" <bart.vanassche@gmail.com>
To: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Andi Kleen" <andi@firstfloor.org>,
"Roland Dreier" <rdreier@cisco.com>,
"Ingo Molnar" <mingo@elte.hu>, "Matthew Wilcox" <matthew@wil.cx>,
"Ingo Oeser" <ioe-lkml@rameria.de>,
"Daniel Walker" <dwalker@mvista.com>,
linux-kernel@vger.kernel.org,
"Linus Torvalds" <torvalds@osdl.org>
Subject: Re: [PATCH] Replace completions with semaphores
Date: Tue, 15 Apr 2008 15:15:32 +0200 [thread overview]
Message-ID: <e2e108260804150615t577dd687u9c093e4f8a9ab923@mail.gmail.com> (raw)
In-Reply-To: <1208249088.7124.7.camel@twins>
On Tue, Apr 15, 2008 at 10:44 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> Also things like lockdep are a real help to a lot of developers - loads
> of locking bugs never make it into the kernel because of it.
I agree that lockdep is a real help for kernel developers. But please
keep in mind that locking order checking has its limitations. While
locking order checking can detect certain very important classes of
deadlocks, it can't detect all classes of possible deadlocks. Consider
e.g. the example mentioned by Roland Dreier, where semaphores are used
to count the number of elements in a queue. Deadlocks triggered by
waiting for a certain semaphore value can't be detected by
lockdep-style algorithms. And renaming semaphores into something else
won't help.
Bart.
next prev parent reply other threads:[~2008-04-15 13:15 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-11 21:00 Matthew Wilcox
2008-04-12 6:43 ` Daniel Walker
2008-04-12 10:31 ` Ingo Oeser
2008-04-12 12:24 ` Peter Zijlstra
2008-04-12 17:26 ` Matthew Wilcox
2008-04-12 18:01 ` Daniel Walker
2008-04-12 18:05 ` Peter Zijlstra
2008-04-12 19:04 ` Matthew Wilcox
2008-04-12 19:16 ` Peter Zijlstra
2008-04-12 19:53 ` Roland Dreier
2008-04-12 20:47 ` Matthew Wilcox
2008-04-13 7:08 ` Ingo Molnar
2008-04-13 12:57 ` Matthew Wilcox
2008-04-14 15:39 ` Ingo Molnar
2008-04-14 15:58 ` Roland Dreier
2008-04-14 16:32 ` Peter Zijlstra
2008-04-14 16:56 ` Arjan van de Ven
2008-04-14 17:50 ` Matthew Wilcox
2008-04-14 17:46 ` Andi Kleen
2008-04-14 17:54 ` Peter Zijlstra
2008-04-14 18:09 ` Daniel Walker
2008-04-14 19:16 ` Andi Kleen
2008-04-15 6:18 ` Bart Van Assche
2008-04-15 6:46 ` Peter Zijlstra
2008-04-15 7:17 ` Bart Van Assche
2008-04-15 8:44 ` Peter Zijlstra
2008-04-15 13:15 ` Bart Van Assche [this message]
2008-04-15 16:09 ` Linus Torvalds
2008-04-15 16:27 ` Andi Kleen
2008-04-15 16:57 ` Linus Torvalds
2008-04-15 17:05 ` Ingo Molnar
2008-04-15 18:50 ` Matthew Wilcox
2008-04-16 12:37 ` Ingo Molnar
2008-04-16 12:50 ` Andi Kleen
2008-04-16 12:59 ` Killable stat/readdir Matthew Wilcox
2008-04-15 17:15 ` [PATCH] Replace completions with semaphores Andi Kleen
2008-04-15 17:26 ` Linus Torvalds
2008-04-15 17:41 ` Matthew Wilcox
2008-04-15 18:14 ` Linus Torvalds
2008-04-16 16:07 ` Ingo Oeser
2008-04-16 16:16 ` Matthew Wilcox
2008-04-16 16:31 ` Oliver Neukum
2008-04-16 16:34 ` Matthew Wilcox
2008-04-16 16:42 ` Oliver Neukum
2008-04-16 16:44 ` Matthew Wilcox
2008-04-16 16:47 ` Roland Dreier
2008-04-16 16:50 ` Arjan van de Ven
2008-04-16 16:58 ` Matthew Wilcox
2008-04-16 17:08 ` Arjan van de Ven
2008-04-16 17:12 ` Matthew Wilcox
2008-04-16 18:10 ` Matthew Wilcox
2008-04-14 19:16 ` Alan Cox
2008-04-13 14:55 ` Bart Van Assche
2008-04-14 17:12 ` API documentation (was [PATCH] Replace completions with semaphores) Jonathan Corbet
2008-04-14 17:33 ` Peter Zijlstra
2008-04-14 18:38 ` Bart Van Assche
2008-04-13 13:55 ` [PATCH] Replace completions with semaphores Bart Van Assche
2008-04-13 14:22 ` Matthew Wilcox
2008-04-13 7:05 ` Ingo Molnar
2008-04-13 12:52 ` Matthew Wilcox
2008-04-14 15:41 ` Ingo Molnar
2008-04-14 17:46 ` Matthew Wilcox
2008-04-14 16:54 ` Jens Axboe
[not found] <ahyFC-2bu-25@gated-at.bofh.it>
[not found] ` <ahUPJ-8rN-1@gated-at.bofh.it>
[not found] ` <ai4vO-2Rp-19@gated-at.bofh.it>
[not found] ` <ai9Yw-5uh-7@gated-at.bofh.it>
[not found] ` <aiz6z-OZ-31@gated-at.bofh.it>
[not found] ` <aizgp-151-25@gated-at.bofh.it>
[not found] ` <aizSW-2Ar-17@gated-at.bofh.it>
[not found] ` <aiAYF-5e7-19@gated-at.bofh.it>
[not found] ` <aiB8o-5A7-17@gated-at.bofh.it>
[not found] ` <aiCnR-7k-39@gated-at.bofh.it>
[not found] ` <aiMGu-7f0-7@gated-at.bofh.it>
2008-04-16 10:22 ` Bodo Eggert
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