RE: Dom0 crashing when built with c/s 881 (Was: [Xen-devel] blktap2: need more than 3 values to unpack)

[Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>]

I'm quitting for the night now, but I see that
the string "nous" is followed by a "b" in the
immediately following word.  Put this together
and you have "nousb"  (read as turn off USB).

Given that the "Driver 'xxx' needs updating"
are for 'usbfs', 'hub', and 'usb', and given
that usb is very related to hotplug, the string
"nousb" where a pair of function pointers should
be is suspicious (though it may also be a complete
coincidence).

I'll try turning off CONFIG_HOTPLUG_PCI tomorrow.

Dan

> -----Original Message-----
> From: Dan Magenheimer 
> Sent: Wednesday, June 03, 2009 7:09 PM
> To: Keir Fraser; Isaku Yamahata
> Cc: Xen-Devel (E-mail)
> Subject: RE: Dom0 crashing when built with c/s 881 (Was: [Xen-devel]
> blktap2: need more than 3 values to unpack)
> 
> 
> > If that doesn't help, I can go add some printk's where that
> > output is happening and see exactly what forces the failure.
> 
> Here's what I am seeing.  Looks like the drv->bus structure
> is getting overwritten with ASCII.
> 
> Driver 'usbfs' needs updating - please use bus_type methods
> drv->bus->probe = 73756f6e  (THAT's "nous" I think)
> drv->probe = d1069ab0
> drv->bus->remove = 00000062
> drv->remove = d1069960
> drv->bus->shutdown = 00000000
> drv->shutdown = 00000000
> usbcore: registered new driver usbfs
> Driver 'hub' needs updating - please use bus_type methods
> drv->bus->probe = 73756f6e
> drv->probe = d1069ab0
> drv->bus->remove = 00000062
> drv->remove = d1069960
> drv->bus->shutdown = 00000000
> drv->shutdown = 00000000
> usbcore: registered new driver hub
> Driver 'usb' needs updating - please use bus_type methods
> drv->bus->probe = 73756f6e
> drv->probe = d1069570
> 
> > -----Original Message-----
> > From: Dan Magenheimer 
> > Sent: Wednesday, June 03, 2009 4:12 PM
> > To: Keir Fraser; Isaku Yamahata
> > Cc: Xen-Devel (E-mail)
> > Subject: RE: Dom0 crashing when built with c/s 881 (Was: [Xen-devel]
> > blktap2: need more than 3 values to unpack)
> > 
> > 
> > > Actually I missed that the dependent code is only built if
> > > CONFIG_PCI_IOMULTI && CONFIG_HOTPLUG_PCI. You've probably got 
> > > one or both
> > > disabled and hence 882 doesn't break without 881 in your case.
> > 
> > In case it helps, with 889 and 881 reverted, I am using the
> > default config which results in CONFIG_PCI_IOMULTI=y and
> > CONFIG_HOTPLUG_PCI=m.
> > 
> > > I can't explain that from reading the code. It looks like a 
> > > no-op to me
> > > unless the new function bus_register_notifier() is called.
> > 
> > Looking at my boot output on failure, there are those lines:
> > 
> > "Driver 'xxx' needs updating - please use bus_type methods"
> > 
> > which is printed in linux/drivers/base/driver.c:driver_register()
> > if a complex set of circumstances are true.  So clearly
> > something is different.
> > 
> > If that doesn't help, I can go add some printk's where that
> > output is happening and see exactly what forces the failure.
> > 
> > Dan
> > 
> > 
> > > -----Original Message-----
> > > From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> > > Sent: Wednesday, June 03, 2009 3:28 PM
> > > To: Dan Magenheimer; Isaku Yamahata
> > > Cc: Xen-Devel (E-mail)
> > > Subject: Re: Dom0 crashing when built with c/s 881 (Was: 
> [Xen-devel]
> > > blktap2: need more than 3 values to unpack)
> > > 
> > > 
> > > On 03/06/2009 22:17, "Dan Magenheimer" 
> > > <dan.magenheimer@xxxxxxxxxx> wrote:
> > > 
> > > >>  1. It only adds extra functionality which by default would
> > > >> not do anything.
> > > >> Just reading the patch I can see it's harmless by itself 
> > > as it merely
> > > >> introduces a new notifier chain which noone registers on.
> > > > 
> > > > I won't pretend to understand the code, but I did
> > > > reproduce the problem with 881 by itself and with
> > > > 889 with 881 reverted.
> > > 
> > > I can't explain that from reading the code. It looks like a 
> > > no-op to me
> > > unless the new function bus_register_notifier() is called.
> > > 
> > > >>  2. Changeset 882 depends on 881. If you revert just 881 then
> > > >> the tree will not build.
> > > > 
> > > > This doesn't appear to be the case for me, though
> > > > I'm certainly willing to believe there's something
> > > > wrong with my process:
> > > 
> > > Actually I missed that the dependent code is only built if
> > > CONFIG_PCI_IOMULTI && CONFIG_HOTPLUG_PCI. You've probably got 
> > > one or both
> > > disabled and hence 882 doesn't break without 881 in your case.
> > > 
> > >  -- Keir
> > > 
> > > 
> > >

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