sio vs sched_lock LOR (was: Re: kern/68442: panic - acquiring
duplicate lock of same type: "sleepq chain")
dl at leo.org
Wed Jun 30 01:05:49 PDT 2004
Colin Percival wrote on Tue, Jun 29, 2004 at 10:58:29PM -0700:
> Regardless of the questionable validity of the other problems this machine
> is encountering, this LOR is real (and ugly). calcru() asserts that it is
> holding sched_lock, but it can printf() about negative runtime or runtime
> going backwards. With a serial console attached, these messages end up at
> siocnputc(), which needs sio_lock.
Yes, I get lots of 'calcru' messages on the console.
> Now, I presume that there is some reason why the locking order hard-coded
> into witness makes it illegal to pick up sio_lock while holding sched_lock,
> but I can't see it. Maybe someone else can explain?
> In the mean time, a workaround for this LOR is to unplug the serial console. :-)
Well, if this keeps the machine from locking up, I'll try it...
- In dieser Mail ist ein Geist, der Dich in den Hintern beisst -
Daniel Lang * dl at leo.org * +49 89 289 18532 * http://www.leo.org/~dl/
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