Date: Sun, 19 Aug 2001 16:21:35 +0900 From: neckpain@nettaxi.com To: current@FreeBSD.ORG Subject: Re: panic kldunload'ing: static sysctl oid too high Message-ID: <200108190721.AAA11589@taxismtp1.alchemyfx.com> In-Reply-To: <200108110622.XAA21343@taxismtp1.alchemyfx.com> References: <200108102252.PAA03031@taxismtp1.alchemyfx.com> <200108110622.XAA21343@taxismtp1.alchemyfx.com>
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On Sat, Aug 11, 2001 at 03:22:21PM +0900, I wrote:
> > - unloading snd_ds1 always panics(either when it's loaded from
> > /boot/loader.conf, or from the command line by kldload).
> > - loading and unloading snd_pcm alone does not panic(snd_pcm is a driver
> > loaded as dependency when snd_ds1 is loaded).
> > - unloading some other modules does not panic.
> > - the last kernel I remember that didn't panic was from 2001.07.20.00.00.00 .
>
> And attached is a patch to kern_sysctl.c I'm using currently as a workaround.
> It just adds a test mode to internal sysctl_remove_oid() and avoid
> reregistering removed oid in sysctl_ctx_free().
Would someone please commit this or any better version? I think this is not
specific to snd_ds1, but a small bug in kern_sysctl.c .
0. A KLD driver allocates an oid with OID_AUTO specified. It's assigned
oid_number >= 0x100.
1. When the driver is unloaded, sysctl_ctx_free() is called from detach
routine in a KLD driver.
2. Inside sysctl_ctx_free(), sysctl_remove_oid() is issued for each context
entry to make sure the entire list can really be freed. If failed,
it tries to restore once removed entries back to the list by
sysctl_register_oid().
3. sysctl_register_oid() rejects a dynamically allocated oid and panic.
The "FIXME" code worked without a pain before kern_sysctl.c, rev 1.112
because sysctl_register_oid() didn't check if oid_number is below the range
reserved for dynamic assignment of oid_number.
[patch in <200108110622.XAA21343@taxismtp1.alchemyfx.com> omitted]
By the way, I found recently that flood-pinging a PCCARD NIC(which shares
irq9 with snd_ds1 driver) seems to make my non-working dsp device play sound.
Really weird.
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