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Subject: Re: [RFC PATCH] x86/apic: Fix BUG due to multiple allocation of
 legacy vectors.
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     x86@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org,
        mingo@redhat.com, bp@alien8.de
References: <20210519233928.2157496-1-imran.f.khan@oracle.com>
 <8735uhddjw.ffs@nanos.tec.linutronix.de>
 <8e1b9002-aa2c-5314-54f6-d5156703e25d@oracle.com>
 <871r9uamu5.ffs@nanos.tec.linutronix.de>
From:   imran.f.khan@oracle.com
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Date:   Thu, 27 May 2021 15:13:26 +1000
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Hi Thomas,

On 26/5/21 12:51 am, Thomas Gleixner wrote:
> Imran,
> 
> On Mon, May 24 2021 at 13:29, imran f. khan wrote:
[...]
> 
>> Even my current setup that was crashing with in-house 5.4 and 5.8
>> kernels, boots fine if I boot it with noapic option removed from kernel
>> boot parameters.
> 
> May I ask the obvious question why the changelog of your patch did not
> mention that this happens only with 'noapic' on the kernel command line?
> 
I was not aware of it earlier. After your first feedback I debugged the 
code further with ML tag and found out about the noapic dependency.
[...]
> 
> Correct. So you almost decoded the underlying problem.
> 
[...]
> So the right thing to do is to ensure that the legacy interrupts are
> marked as system vectors in case that the IO/APIC is disabled via
> config, kernel command line or lack of enumeration. See below.
> 
Thanks for clarifying it. I have tested your change in my local setup as 
well and it works well.

Thanks,
Imran