[PATCH v2 04/11] USB: chipidea: clear gadget struct at udc_start fail path

[Alexander Shishkin]

Richard Zhao <richard.zhao at freescale.com> writes:

> On Tue, Aug 28, 2012 at 11:29:35AM +0300, Alexander Shishkin wrote:
>> Richard Zhao <richard.zhao at freescale.com> writes:
>> 
>> > States in gadget are not needed any more, set it to zero.
>> 
>> It's generally a good practice to mention in the commit message what is
>> it that you are fixing with this patch.
> It fixes the following dump if udc_start register gadget->dev but fail
> the start process:
> kobject (bf8330a0): tried to init an initialized object, something is seriously wrong.
> [<80011d90>] (dump_backtrace+0x0/0x10c) from [<804b65ac>] (dump_stack+0x18/0x1c)
> [<804b6594>] (dump_stack+0x0/0x1c) from [<80247d98>] (kobject_init+0x7c/0x9c)
> [<80247d1c>] (kobject_init+0x0/0x9c) from [<802a3870>] (device_initialize+0x28/0x70)
> [<802a3848>] (device_initialize+0x0/0x70) from [<802a4798>] (device_register+0x14/0x20)
> [<802a4784>] (device_register+0x0/0x20) from [<80359a70>] (udc_start+0x180/0x2c8)
> [<803598f0>] (udc_start+0x0/0x2c8) from [<80356e9c>] (ci_role_work+0xc8/0xec)
> [<80356dd4>] (ci_role_work+0x0/0xec) from [<8003a8a0>] (process_one_work+0x158/0x474)
> [<8003a748>] (process_one_work+0x0/0x474) from [<8003af6c>] (worker_thread+0x140/0x3b4)
> [<8003ae2c>] (worker_thread+0x0/0x3b4) from [<8003fe60>] (kthread+0x90/0x9c)
> [<8003fdd0>] (kthread+0x0/0x9c) from [<8002774c>] (do_exit+0x0/0x350)
>> 
>> > Signed-off-by: Richard Zhao <richard.zhao at freescale.com>
>> > ---
>> >  drivers/usb/chipidea/udc.c |    1 +
>> >  1 file changed, 1 insertion(+)
>> >
>> > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
>> > index c7a032a..9fb6394 100644
>> > --- a/drivers/usb/chipidea/udc.c
>> > +++ b/drivers/usb/chipidea/udc.c
>> > @@ -1746,6 +1746,7 @@ free_pools:
>> >  	dma_pool_destroy(ci->td_pool);
>> >  free_qh_pool:
>> >  	dma_pool_destroy(ci->qh_pool);
>> > +	memset(&ci->gadget, 0, sizeof(ci->gadget));
>> 
>> I understand that you're probably hitting "kobject already initialized"
>> warning here, but I think the real problem is that this function gets
>> called twice and fails the first time. Why does that happen?
> I saw the dump at early stage of adding imx otg support, when there's
> things not ready. I think it's less important why udc_start fail,
> because no one enable imx otg before.  It's important when it fails,
> the dump shows up.

I'd prefer that whenever udc_start() fails it doesn't go unnoticed,
except probably for the cases when it fails due to transceiver not being
ready at the probe time, which needs to be handled separately.

Regards,
--
Alex