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Date: Wed, 24 Oct 2012 11:25:46 -0700
From: Jonathan Nieder <jrnieder@gmail.com>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Greg KH <gregkh@linuxfoundation.org>, linbao.zhang@hp.com
Subject: Re: [stable 2.6.32..2.6.34] x86, ioapic: initialize
 nr_ioapic_registers early in mp_register_ioapic()
Message-ID: <20121024182546.GB3338@elie.Belkin>
References: <1351102644.6017.72.camel@sbsiddha-desk.sc.intel.com>
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Hi Suresh,

Suresh Siddha wrote:

[...]
> This problem doesn't happen with more recent kernels and closer
> look at the 2.6.32 kernel shows that the code which masks
> the IO-APIC RTE's is not working as expected as the nr_ioapic_registers
> for each IO-APIC is not yet initialized at this point. In the later
> kernels we initialize nr_ioapic_registers much before and
> everything works as expected.
>
> For 2.6.[32..34] kernels, fix this issue by initializing
> nr_ioapic_registers early in mp_register_ioapic()
>
> Relevant upstream commit info:
>
> commit 7716a5c4ff5f1f3dc5e9edcab125cbf7fceef0af

Why not cherry-pick 7716a5c4ff5 in full?

Curious,
Jonathan