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Subject: Re: [RFC PATCH v2 3/4] acpi: apei: Do not panic() when correctable
 errors are marked as fatal.
To:     James Morse <james.morse@arm.com>
Cc:     Borislav Petkov <bp@alien8.de>, linux-acpi@vger.kernel.org,
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References: <20180416215903.7318-1-mr.nuke.me@gmail.com>
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 <e5e107e7-e18e-725a-8f9b-95e6f033ab45@arm.com>
From:   "Alex G." <mr.nuke.me@gmail.com>
Message-ID: <aa20a835-4059-f695-a0cf-f862d6313e17@gmail.com>
Date:   Thu, 19 Apr 2018 11:27:52 -0500
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On 04/19/2018 10:35 AM, James Morse wrote:
> Hi Alex,
> 
> (I haven't read through all this yet, just on this one:)
> 
> On 04/19/2018 03:57 PM, Alex G. wrote:
>> Maybe it's better move the AER handling to NMI/IRQ context, since
>> ghes_handle_aer() is only scheduling the real AER andler, and is irq
>> safe. I'm scratching my head about why we're messing with IRQ work from
>> NMI context, instead of just scheduling a regular handler to take care
>> of things.
> 
> We can't touch schedule_work_on() from NMI context as it takes spinlocks
> and
> disables interrupts. (see __queue_work()) The NMI may have interrupted
> IRQ-context code
> that was already holding the same locks.
> 
> IRQ-work behaves differently, it uses an llist for the work and an arch
> code hook
> to raise a self-IPI.

That makes sense. Thank you!

Alex

> 
> Thanks,
> 
> James