From: "Russ Cox" <rsc@plan9.bell-labs.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] usb/usbaudio and output speed?
Date: Fri, 25 Oct 2002 11:56:44 -0400 [thread overview]
Message-ID: <156ffeb6f85f1b8d171e4b4cfce223cc@plan9.bell-labs.com> (raw)
term% usb/usbd
term% usb/usbaudio
term% usb/usbaudio # Note, invoking usb/usbaudio twice.
term% kill usbaudio | rc
This is a problem in the usb driver.
It still doesn't the explain the other
ps hangs I've seen. In general, ps hangs
because some proc's p->debug gets locked
and never unlocked. Then opening that
proc's status file hangs.
In this case, postnote got confused because
a rendez structure got freed while a process
was still sleeping on it. The result was that
postnote just keeps looping staring at this
freed memory, which will never again look like
an available lock. Postnote is sitting on p->debug
while doing this. Usually the looping doesn't
happen or loops once just to deal with transient
lock ordering problems. It can't really do much
when it's been pointed at bad memory.
If anyone has any other reliable recipes for
making ps hang, I'm still all ears. The
hangs I've seen had nothing to do with usb.
Russ
next reply other threads:[~2002-10-25 15:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-25 15:56 Russ Cox [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-10-24 17:31 nigel
2002-10-24 17:37 ` Dan Cross
2002-10-23 20:12 Russ Cox
2002-10-23 21:40 ` Dan Cross
2002-10-24 13:49 ` Dan Cross
2002-10-24 14:27 ` Boyd Roberts
2002-10-24 15:52 ` Aharon Robbins
2002-10-25 4:58 ` Jim Choate
2002-10-24 17:07 ` Dan Cross
2002-10-25 9:04 ` Anthony Mandic
2002-10-23 0:40 Russ Cox
2002-10-23 18:38 ` Dan Cross
2002-10-23 0:00 Russ Cox
2002-10-23 0:28 ` Dan Cross
2002-10-22 19:21 Dan Cross
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