udev related ? (Was Re: rmmod deadlocks with 2.6.5-rc[2,3])

From: Frédéric L. W. Meunier
Date: Tue Mar 30 2004 - 18:02:04 EST

OK, I gave 2.6.3-rc3-mm1 a try and could reproduce it.

I still compile with CONFIG_DEVFS_FS=y and
CONFIG_DEVFS_MOUNT=y, but to use udev boot with devfs=nomount.

I then booted with devfs=mount acpi=off noapic. Guess what ? I
was able to unmount all offending modules.

What next ? Boot with devfs=mount to see if ACPI was to blame.
No, it wasn't.

My /etc/rc.d/rc.S is very simple:

[ -e /dev/.devfsd -a -x /sbin/devfsd ] && devfsd /dev

(only run devfsd if devfs is mounted)

mount -vn -t proc proc /proc # Needed for LABEL= in /etc/fstab

mount -vn -t sysfs sysfs /sys

[ ! -e /dev/.devfsd -a -d /sys/block ] && /etc/rc.d/start_udev

(only run start_udev if devfs isn't mounted and sysfs is

Since 2.6.4 works fine for me using devfs=nomount, something is
broken. I'm using the latest udev and hotplug.

I'm attaching a strace of a rmmod that failed.

On Tue, 30 Mar 2004, Frédéric L. W. Meunier wrote:

> On Tue, 30 Mar 2004, Daniel Drake wrote:
> > Frédéric L. W. Meunier wrote:
> > > If I boot with 2.6.5-rc[2,3] and use rmmod snd_via82xx or rmmod
> > > ohci_hcd (it doesn't happen with all modules), rmmod deadlocks.
> > > 2.6.4 works fine.
> >
> > The ohci_hcd problem should be temporarily fixed by a recent
> > patch to this list, from Greg KH (subject: [PATCH] USB:
> > Eliminate wait following interface unregistration). This
> > worked for me.
> I forgot to report that I don't need OHCI. It's hotplug which
> loads it for some reason under 2.6, but not under 2.4.
> > As for the snd_ modules, this is a different problem, which I
> > am still experiencing. I have had it with both snd_emu10k1
> > and snd_intel8x0 - but it does not happen every time. I have
> > experienced it on 2.6.5-rc2 and -rc3 (plus their -mm
> > patches). rmmod hangs and doesnt respond to kill -9.
> I used ALSA from CVS.
> > Is there any output I can capture to diagnose this?
> Here nothing gets printed. Maybe strace can help. But I'll
> wait.
> It also happened removing i2c_isa when I went through removing
> all modules. Nothing wrong with joydev, adi, gameport, it87...


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