From: Steven Rostedt <srostedt@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
David Miller <davem@davemloft.net>,
hugh@veritas.com, mingo@elte.hu, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, davej@redhat.com
Subject: Re: [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock()
Date: Wed, 08 Oct 2008 12:53:56 -0400 [thread overview]
Message-ID: <48ECE5A4.1040003@redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.00.0810080906520.3208@nehalem.linux-foundation.org>
Linus Torvalds wrote:
>
>
> I know for a fact that some people thought unlocking in non-nested order
> was a bug. And I believe that belief is a dangerous one.
>
Ah, OK. You are fighting against nesting nazis, fair enough.
I have written a bit of code where nesting was not possible (similar to
your example, but I call those traversal locking not nesting). I just
find that
the locks should be nested when the nesting is natural. Breaking the nesting
on natural nesting locks is a bug, IMHO. But as you know, there are several
programmers out there that can not determine the difference between natural
nesting locks and non nesting locks.
By adding such a rule, those that can not tell the difference will be
making a
lot of needless noise, hence, it is best not to make any such rule.
Lesson learned. I'll now go back to debugging my code.
-- Steve
next prev parent reply other threads:[~2008-10-08 16:55 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-04 13:03 [RFC][PATCH 0/7] lockdep Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 1/7] lockdep: Fix combinatorial explosion in lock subgraph traversal Peter Zijlstra
2008-08-05 8:34 ` David Miller
2008-08-05 8:46 ` Peter Zijlstra
2008-08-13 3:48 ` Tim Pepper
2008-08-13 10:56 ` Ingo Molnar
2008-08-04 13:03 ` [RFC][PATCH 2/7] lockdep: lock_set_subclass - reset a held locks subclass Peter Zijlstra
2008-08-05 8:35 ` David Miller
2008-08-04 13:03 ` [RFC][PATCH 3/7] lockdep: re-annotate scheduler runqueues Peter Zijlstra
2008-08-05 8:35 ` David Miller
2008-08-04 13:03 ` [RFC][PATCH 4/7] lockdep: shrink held_lock structure Peter Zijlstra
2008-08-05 16:08 ` Peter Zijlstra
2008-08-06 7:17 ` Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 5/7] lockdep: map_acquire Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 6/7] lockdep: lock protection locks Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock() Peter Zijlstra
2008-08-04 14:07 ` Roland Dreier
2008-08-04 14:19 ` Peter Zijlstra
2008-08-04 14:26 ` Roland Dreier
2008-08-04 14:32 ` Peter Zijlstra
2008-08-04 14:53 ` Dave Jones
2008-08-04 14:56 ` Peter Zijlstra
2008-08-04 16:26 ` Andrea Arcangeli
2008-08-04 16:38 ` Peter Zijlstra
2008-08-04 17:27 ` Andrea Arcangeli
2008-08-04 17:46 ` Andrea Arcangeli
2008-08-04 17:57 ` [PATCH] workaround minor lockdep bug triggered by mm_take_all_locks Andrea Arcangeli
2008-08-04 18:48 ` Peter Zijlstra
2008-08-04 18:56 ` Roland Dreier
2008-08-04 19:05 ` Peter Zijlstra
2008-08-04 20:15 ` Andrea Arcangeli
2008-08-04 20:37 ` Peter Zijlstra
2008-08-04 21:09 ` Andrea Arcangeli
2008-08-04 21:14 ` Pekka Enberg
2008-08-04 21:30 ` Andrea Arcangeli
2008-08-04 21:41 ` Andrew Morton
2008-08-04 22:12 ` Andrea Arcangeli
2008-08-04 21:42 ` Arjan van de Ven
2008-08-04 22:30 ` Andrea Arcangeli
2008-08-04 23:38 ` Arjan van de Ven
2008-08-05 0:47 ` Andrea Arcangeli
2008-08-04 21:27 ` Arjan van de Ven
2008-08-04 21:54 ` Andrea Arcangeli
2008-08-04 21:57 ` David Miller
2008-08-05 2:00 ` Roland Dreier
2008-08-05 2:18 ` Andrea Arcangeli
2008-08-05 12:02 ` Roland Dreier
2008-08-05 12:20 ` Andrea Arcangeli
2008-08-04 18:48 ` [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock() Peter Zijlstra
2008-08-04 21:32 ` David Miller
2008-08-04 18:06 ` Jeremy Fitzhardinge
2008-08-04 18:54 ` Peter Zijlstra
2008-08-04 19:26 ` Jeremy Fitzhardinge
2008-08-04 19:31 ` Linus Torvalds
2008-08-04 19:39 ` Peter Zijlstra
2008-08-04 20:16 ` Jeremy Fitzhardinge
2008-10-08 15:27 ` Steven Rostedt
2008-10-08 15:43 ` Linus Torvalds
2008-10-08 16:03 ` Steven Rostedt
2008-10-08 16:19 ` Linus Torvalds
2008-10-08 16:53 ` Steven Rostedt [this message]
2008-10-08 15:52 ` Nick Piggin
2008-10-08 17:18 ` Steven Rostedt
2008-08-07 11:25 ` Peter Zijlstra
2008-08-07 11:25 ` [RFC][PATCH 8/7] lockdep: annotate mm_take_all_locks() Peter Zijlstra
2008-08-07 11:25 ` [RFC][PATCH 9/7] mm: fix mm_take_all_locks() locking order Peter Zijlstra
2008-08-07 12:14 ` Hugh Dickins
2008-08-07 12:41 ` Peter Zijlstra
2008-08-07 13:27 ` Hugh Dickins
2008-08-07 21:46 ` Andrea Arcangeli
2008-08-08 1:34 ` Andrea Arcangeli
2008-08-08 7:16 ` Peter Zijlstra
2008-08-11 10:08 ` [RFC][PATCH 0/7] lockdep Ingo Molnar
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=48ECE5A4.1040003@redhat.com \
--to=srostedt@redhat.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=davej@redhat.com \
--cc=davem@davemloft.net \
--cc=hugh@veritas.com \
--cc=jeremy@goop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rostedt@goodmis.org \
--cc=torvalds@linux-foundation.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.