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Date: Wed, 30 Jan 2013 23:03:26 +0200
From: Andriy Gapon <avg@FreeBSD.org>
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To: freebsd-hackers <freebsd-hackers@FreeBSD.org>
Subject: [clang] NMI while trying to read acpi timer register
References: <51068B74.2070808@FreeBSD.org>
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on 28/01/2013 16:30 Andriy Gapon said the following:
> is there any reasonable explanation for getting an NMI while trying to read acpi
> timer register?
> Note: this happens only after ACPI suspend/resume.

An update.
This happens only with clang compiled kernel, gcc compiled kernel is OK.
Also, this happens only in the depth of fwohci driver (where it calls DELAY).
If firewire is not loaded, then there is no problem.

I suspect that perhaps there is some miscompilation that results in some
incorrect I/O access that later leads to NMI.  Too many unknowns and guesses
here, obviously.

-- 
Andriy Gapon