From mboxrd@z Thu Jan 1 00:00:00 1970 From: richard.zhao@freescale.com (Richard Zhao) Date: Tue, 28 Aug 2012 17:09:43 +0800 Subject: [PATCH v2 04/11] USB: chipidea: clear gadget struct at udc_start fail path In-Reply-To: <87oblv2zdc.fsf@ashishki-desk.ger.corp.intel.com> References: <1346137397-32374-1-git-send-email-richard.zhao@freescale.com> <1346137397-32374-5-git-send-email-richard.zhao@freescale.com> <87oblv2zdc.fsf@ashishki-desk.ger.corp.intel.com> Message-ID: <20120828090942.GX4011@b20223-02.ap.freescale.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Aug 28, 2012 at 11:29:35AM +0300, Alexander Shishkin wrote: > Richard Zhao 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 > > --- > > 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. Thanks Richard > > In any case, please elaborate on the problem. > > Regards, > -- > Alex >