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 id 1Xq4US-000Dx0-K6; Sun, 16 Nov 2014 18:24:01 +0000
Subject: Re: USB locks up system -- WAS Re: shutdown or acpi problem
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From: Mark R V Murray <markm@FreeBSD.org>
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Date: Sun, 16 Nov 2014 18:23:59 +0000
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References: <20141112224212.GA14013@troutmask.apl.washington.edu>
 <20141113172533.GA18690@troutmask.apl.washington.edu>
 <20141113180332.GA18990@troutmask.apl.washington.edu>
 <20141113181515.GA19117@troutmask.apl.washington.edu>
 <546515BF.6030508@selasky.org>
 <20141113212206.GA20802@troutmask.apl.washington.edu>
 <20141116054141.GA33186@troutmask.apl.washington.edu>
 <CAJ-Vmo=8oQdi_5um3ck+Qwb=4KL2QfHE=ykQ2mNTJc5QerOEuw@mail.gmail.com>
 <20141116175102.GA35649@troutmask.apl.washington.edu>
 <D5925789-834A-42C8-9854-2E055592DA46@FreeBSD.org>
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To: Ian Lepore <ian@FreeBSD.org>
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Cc: Hans Petter Selasky <hps@selasky.org>, Adrian Chadd <adrian@freebsd.org>,
 freebsd-current <freebsd-current@freebsd.org>,
 Dag-Erling Sm?rgrav <des@freebsd.org>,
 Steve Kargl <sgk@troutmask.apl.washington.edu>
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> On 16 Nov 2014, at 18:21, Ian Lepore <ian@FreeBSD.org> wrote:
>=20
> On Sun, 2014-11-16 at 18:17 +0000, Mark R V Murray wrote:
>>> On 16 Nov 2014, at 17:51, Steve Kargl =
<sgk@troutmask.apl.washington.edu> wrote:
>>>=20
>>> Is there a 'random: device_detach():' missing between the 'umass0'
>>> and 'da0' messages in the last 4 lines.
>>=20
>> No. At attach time, the RNG grabs some probe entropy. At detach time =
it does nothing.
>>=20
>> M
>=20
> And yet... Steve has gathered evidence that the system bricks when a
> device is detached with the new entropy-gathering code and doesn't do =
so
> prior to that code.  What else is the new code doing around detach =
time?

Nothing, except possibly harvesting interrupt entropy. I=E2=80=99ll =
promise to be
astonished if this is other-than-harmless.

I=E2=80=99d be more suspicious of the harvester thread, but I still =
can=E2=80=99t see how
its hurting :-(

M
--=20
Mark R V Murray