From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <156ffeb6f85f1b8d171e4b4cfce223cc@plan9.bell-labs.com> From: "Russ Cox" To: 9fans@cse.psu.edu Subject: Re: [9fans] usb/usbaudio and output speed? MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Fri, 25 Oct 2002 11:56:44 -0400 Topicbox-Message-UUID: 0e2aa4a4-eacb-11e9-9e20-41e7f4b1d025 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