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Date: Mon, 29 Aug 2011 11:29:35 +0300
From: Andriy Gapon <avg@FreeBSD.org>
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To: Hans Petter Selasky <hselasky@FreeBSD.org>
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Cc: freebsd-arch@FreeBSD.org
Subject: Re: skipping locks, mutex_owned, usb
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on 28/08/2011 12:27 Hans Petter Selasky said the following:
> On Sunday 28 August 2011 11:25:51 Andriy Gapon wrote:
>> So many unconventional tricks.
> 
> Similar code is used in the DROP_GIANT and PICKUP_GIANT macros.

Thank you for pointing this out - I was unfair to the USB code.
This changes my perspective of the mtx_owned issue a little bit...
OTOH, it looks like DROP_GIANT/PICKUP_GIANT are used in the code paths that
should not be exercised in the post-panic / dumping environment.
Except, perhaps, for the sync-on-panic option, which needs to be re-worked anyways.

> You might want 
> to check all references to mtx_owned() in the kernel, and make a set of 
> exceptions for post-panic code execution.

$ glimpse mtx_owned | wc -l
     152

This looks like a too large plate for me :-(

-- 
Andriy Gapon