From mboxrd@z Thu Jan 1 00:00:00 1970 From: robert.jarzmik@free.fr (Robert Jarzmik) Date: Mon, 13 Feb 2017 20:29:36 +0100 Subject: [BUG] usb: gadget: Kernel oops with UVC USB gadget and configfs In-Reply-To: <840f1745-8792-9d7b-9f43-961614b6938d@tul.cz> (Petr Cvek's message of "Mon, 13 Feb 2017 04:04:32 +0100") References: <497c3c61-31f0-4d40-9bab-5a0aa793e5e9@tul.cz> <87shnt1sue.fsf@belgarion.home> <3faadfcb-5e0d-8f92-3e91-4bd745026644@tul.cz> <8737fj1us3.fsf@belgarion.home> <840f1745-8792-9d7b-9f43-961614b6938d@tul.cz> Message-ID: <87r331zy73.fsf@belgarion.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Petr Cvek writes: > Dne 12.2.2017 v 13:02 Robert Jarzmik napsal(a): > That's weird I even removed pxa_set_udc_info() from magician machine init and it still fails. > Host cable and/or actual camera is not required. It fails without them. > > So you binded pxa27x-udc as UDC controller (= activated it) and then rmmoded > it and nobody complained? No, that usecase actually fails. I think you could submit a proper patch with the diff in [1], with which the pxa27x-udc unloading will work. But it's not _your_ testcase, as per your provided callstack : [ 2152.826529] [] (udc_bind_to_driver [udc_core]) from [] (usb_add_gadget_udc_release+0x138/0x21c [udc_core]) [ 2152.826731] [] (usb_add_gadget_udc_release [udc_core]) from [] (pxa_udc_probe+0x290/0x2fc [pxa27x_udc]) [ 2152.833554] [] (pxa_udc_probe [pxa27x_udc]) from [] (platform_drv_probe+0x38/0x84) [ 2152.833602] [] (platform_drv_probe) from [] (driver_probe_device+0x1e0/0x3f4) Your problem seems in the pxa_udc_probe(), which I would presume you're doing for a second time, ie. after modprobe pxa27x_udc + bind UDC controller + rmmod pxa27x_udc + modprobe pxa27x_udc. I suspect that in this case, the problem is that the rmmod works while udc is still bound to the composite. The lsmod seems to prove that the refcount is still 0 while usb_f_uvc is is bound to pxa27x_udc. [@Felipe and @Laurent] I have no knowledge of usb_f_uvc, so would you tell me if binding usb_f_uvc to pxa27_udc should have incremented the module refcount of pxa27x_udc or not ? > Can you try v4.10? Or send me exact commit on what you tested it so I can test > it too. My top commit (not counting yours) is : 61c04572de40 ("Merge branch 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux") Cheers. -- Robert [1] diff --git a/drivers/usb/gadget/udc/pxa27x_udc.c b/drivers/usb/gadget/udc/pxa27x_udc.c index 9fb103348b5d..a239eb836652 100644 --- a/drivers/usb/gadget/udc/pxa27x_udc.c +++ b/drivers/usb/gadget/udc/pxa27x_udc.c @@ -2512,7 +2512,8 @@ static int pxa_udc_remove(struct platform_device *_dev) usb_del_gadget_udc(&udc->gadget); pxa_cleanup_debugfs(udc); - usb_put_phy(udc->transceiver); + if (!IS_ERR(udc->transceiver)) + usb_put_phy(udc->transceiver); udc->transceiver = NULL; the_controller = NULL;