Re: Panic with ugen

From: Daan Vreeken [PA4DAN] <Danovitsch_at_Vitsch.net>
Date: Thu, 27 Nov 2003 08:56:44 +0100
On Thursday 27 November 2003 01:08, Jay Cornwall wrote:
> > It looks like this:
> >
> > panic()
> > destroy_dev()
> > ugen_destroy_devnodes()
> > ugen_set_config()
>
> Yes, that's the one, and I think I can see why. The existing code fixed
> devfs problems for normal ugen_set_config calls, but doesn't account for
> what happens when an error occurs (which is presumably happening in your
> example program, as you said it gives an error the first time round) - the
> devfs stuff only half completes.
>
> (actually, looking at that error handling code, it doesn't look like it's
> been thought through well anyway - /* XXX should only do this after setting
> new altno has succeeded */ - maybe time to clean this code up?)
>
> After the device endpoints are destroyed (sys/dev/ugen.c:1038), the returns
> on lines 1055 and 1058 need to be covered by a devnode recovery procedure -
> particularly tricky given we just wiped the endpoint descriptors clean.
>
> I'll look at restructuring this code tomorrow, if Bernd doesn't beat me to
> it.
If you have time left, could you perhaps also have a look at kern/51186?
I have filed it back in March and it's still open. (Fixes a memory corruption 
bug in ugen).

grtz,
Daan
Received on Wed Nov 26 2003 - 22:56:15 UTC

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