Re: 2.6.20.git regression: 'PCI: add the sysfs driver name to all modules' causes hard hang on boot

Mike Galbraith
2007-02-18T09:27:37Z

On Sun, 2007-02-18 at 09:02 +0100, Mike Galbraith wrote:

> The reason it's hanging is that nobody releases the driver, so we wait
> forever in driver_unregister(). With the below, box boots fine...
>
> --- drivers/base/bus.c.org 2007-02-18 08:38:57.000000000 +0100
> +++ drivers/base/bus.c 2007-02-18 08:39:09.000000000 +0100
> @@ -593,6 +593,7 @@ void bus_remove_driver(struct device_dri
> driver_detach(drv);
> module_remove_driver(drv);
> kobject_unregister(&drv->kobj);
> + driver_release(&drv->kobj);
> put_bus(drv->bus);
> }
>
>
> ...but that can't be right given that the darn thing booted just fine
> prior to the naming patch with an equally unhappy init_ipmi_si(). Hmm.

Ok. The path it's supposed to take to driver_release() goes like so....

[ 17.495312] bus platform: add driver ipmi
[ 17.506560] ipmi message handler version 39.1
[ 17.518099] ipmi device interface
[ 17.528491] device class 'ipmi': registering
[ 17.539854] bus platform: add driver ipmi_si
[ 17.551210] IPMI System Interface driver.
[ 17.562242] bus pci: add driver ipmi_si
[ 17.583686] bus pci: remove driver ipmi_si
[ 17.594721] BUG: at drivers/base/bus.c:65 driver_release()
[ 17.607224] [<c0105136>] show_trace_log_lvl+0x1a/0x30
[ 17.619434] [<c0105862>] show_trace+0x12/0x14
[ 17.630822] [<c0105906>] dump_stack+0x16/0x18
[ 17.642098] [<c034b632>] driver_release+0x37/0x39
[ 17.653703] [<c02c73b9>] kobject_cleanup+0x43/0x64
[ 17.665359] [<c02c73e5>] kobject_release+0xb/0xd
[ 17.676748] [<c02c8017>] kref_put+0x28/0x8c
[ 17.687626] [<c02c7374>] kobject_put+0x14/0x16
[ 17.698712] [<c02c74c4>] kobject_unregister+0x22/0x25
[ 17.710359] [<c034b7e0>] bus_remove_driver+0x95/0xa5
[ 17.721911] [<c034c87b>] driver_unregister+0xe/0x47
[ 17.733317] [<c02d59ac>] pci_unregister_driver+0x13/0x73
[ 17.745149] [<c033e141>] init_ipmi_si+0x798/0x7ba
[ 17.756339] [<c065b58c>] init+0x114/0x23c
[ 17.766748] [<c0104dab>] kernel_thread_helper+0x7/0x1c

...so I guess it's a ref counting problem somewhere.

-Mike