From: Jarek Poplawski <jarkao2@o2.pl>
To: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alexey Dobriyan <adobriyan@sw.ru>,
linux-kernel@vger.kernel.org
Subject: Re: 2.6.23-rc6-mm1: IPC: sleeping function called ...
Date: Thu, 20 Sep 2007 15:26:28 +0200 [thread overview]
Message-ID: <20070920132628.GC2796@ff.dom.local> (raw)
In-Reply-To: <46F270DA.5030101@bull.net>
On Thu, Sep 20, 2007 at 03:08:42PM +0200, Nadia Derbey wrote:
...
> So, here is the ipc_lock_by_ptr() status:
> 1) do_msgsnd(), semctl_main(GETALL), semctl_main(SETALL) and find_undo()
> call it inside a refcounting.
> ==> no rcu read section needed.
>
> 2) *_exit_ns(), ipc_findkey() and sysvipc_find_ipc() call it under the
> ipc_ids mutex lock.
> ==> no rcu read section needed.
>
> 3) do_msgrcv() is the only path where ipc_lock_by_ptr() is not called
> under refcounting
> ==> rcu read section + some more checks needed once the spnlock is
> taken.
>
> So I completely agree with you: we might remove the rcu_read_lock() from
> the ipc_lock_by_ptr() and explicitley call it when needed (actually, it
> is already explicitly called in do_msgrcv()).
Impossible!
I've to look at this once more in the evening (and try to recall
what I've seen yesterday and forgotten today...).
Cheers,
Jarek P.
next prev parent reply other threads:[~2007-09-20 13:24 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-18 9:17 2.6.23-rc6-mm1: IPC: sleeping function called Alexey Dobriyan
2007-09-18 9:42 ` Andrew Morton
2007-09-18 10:17 ` Andrew Morton
2007-09-18 10:30 ` Nadia Derbey
2007-09-18 10:34 ` Andrew Morton
[not found] ` <20070918142451.418b3b51@twins>
2007-09-18 16:13 ` Paul E. McKenney
2007-09-18 16:57 ` Andrew Morton
2007-09-18 18:29 ` Paul E. McKenney
2007-09-18 19:41 ` Peter Zijlstra
2007-09-18 20:26 ` [PATCH 1/2] lockdep: annotate rcu_read_lock() Peter Zijlstra
2007-09-18 20:27 ` [RFC][PATCH 2/2] lockdep: rcu_dereference() vs rcu_read_lock() Peter Zijlstra
2007-09-18 21:21 ` Paul E. McKenney
2007-09-18 10:27 ` 2.6.23-rc6-mm1: IPC: sleeping function called Andrew Morton
2007-09-18 10:32 ` Alexey Dobriyan
2007-09-18 14:55 ` Nadia Derbey
2007-09-18 17:01 ` Andrew Morton
2007-09-21 9:18 ` Nadia Derbey
2007-09-19 14:07 ` Jarek Poplawski
2007-09-20 6:24 ` Nadia Derbey
2007-09-20 7:28 ` Jarek Poplawski
2007-09-20 8:21 ` Jarek Poplawski
2007-09-20 8:52 ` Nadia Derbey
2007-09-20 13:08 ` Nadia Derbey
2007-09-20 13:26 ` Jarek Poplawski [this message]
2007-09-21 8:44 ` Jarek Poplawski
2007-09-21 10:11 ` Nadia Derbey
2007-09-21 11:03 ` Jarek Poplawski
2007-09-21 11:15 ` Jarek Poplawski
2007-09-24 6:54 ` Jarek Poplawski
2007-09-24 7:43 ` Jarek Poplawski
2007-09-24 8:18 ` Nadia Derbey
2007-09-24 9:50 ` Nadia Derbey
2007-09-25 11:47 ` Jarek Poplawski
2007-09-26 6:13 ` Jarek Poplawski
2007-09-20 13:19 ` Jarek Poplawski
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