Date: Mon, 02 Nov 2009 22:02:43 -0500 (EST)
From: Len Brown <lenb@kernel.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: "Luis R. Rodriguez" <mcgrof@gmail.com>, linux-kernel@vger.kernel.org,
       linux-acpi@vger.kernel.org
Subject: Re: scheduling while atomic acpi_idle_enter_bm
In-reply-to: <20091027165345.3237d3df@infradead.org>
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 <20091027165345.3237d3df@infradead.org>
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> > I get this when modprobing some module I am working on. I figured it
> > was the module's fault but the EIP points to something else so I am
> > not sure. I get the following repeating about 4 times on 2.6.32-rc5:
> 
> 
> you can get this if your own code leaves interrupts disabled in a
> kernel thread and then lets the cpu go idle...

Unclear.

acpi_enter_idle_bm() assumes that it is entered with irqs enabled,
and so it we unconditionally disables IRQs.

Then we unconditionally re-enable them.

The problem seems to be that right after we enable them,
we find that they are actually disabled, perhaps as
a side-effect of SMM.

Is your machine a Dell, per chance?

Please test the patches in this bug report:
http://bugzilla.kernel.org/show_bug.cgi?id=14101

thanks,
Len Brown, Intel Open Source Technology Center 
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