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Date: Fri, 11 Mar 2005 10:11:42 +0100
From: Jan Kasprzak <kas@fi.muni.cz>
To: Andrew Morton <akpm@osdl.org>
Cc: Paul Mackerras <paulus@samba.org>, Jean Tourrilhes <jt@bougret.hpl.hp.com>,
       javier@tudela.mad.ttd.net, linux-fbdev-devel@lists.sourceforge.net,
       acpi-devel@lists.sourceforge.net, linux1394-devel@lists.sourceforge.net,
       Roland Dreier <roland@topspin.com>, linux-kernel@vger.kernel.org
Subject: Re: [ACPI] inappropriate use of in_atomic()
Message-ID: <20050311091142.GB22415@fi.muni.cz>
References: <20050310204006.48286d17.akpm@osdl.org>
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Andrew Morton wrote:
: 
: in_atomic() is not a reliable indication of whether it is currently safe
: to call schedule().
: 
: This is because the lockdepth beancounting which in_atomic() uses is only
: accumulated if CONFIG_PREEMPT=y.  in_atomic() will return false inside
: spinlocks if CONFIG_PREEMPT=n.
: 
: Consequently the use of in_atomic() in the below files is probably
: deadlocky if CONFIG_PREEMPT=n:
[...]
: 	drivers/acpi/osl.c
[...]

This may be the cause of 

http://bugme.osdl.org/show_bug.cgi?id=4150

- I have recently verified that the problem described in bug #4150 disappears
when CONFIG_PREEMPT=y is used.

-Yenya


-- 
| Jan "Yenya" Kasprzak  <kas at {fi.muni.cz - work | yenya.net - private}> |
| GPG: ID 1024/D3498839      Fingerprint 0D99A7FB206605D7 8B35FCDE05B18A5E |
| http://www.fi.muni.cz/~kas/   Czech Linux Homepage: http://www.linux.cz/ |
> Whatever the Java applications and desktop dances may lead to, Unix will <
> still be pushing the packets around for a quite a while.      --Rob Pike <
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