Hi, "He, Bo" <bo.he@xxxxxxxxx> writes: > the patch is for fix the below kernel panic: > BUG: unable to handle kernel NULL pointer dereference at 000000000000002a > IP: [<ffffffff8170e19d>] composite_setup+0x3d/0x1830 > PGD 27525b067 PUD 27525a067 PMD 0 > Oops: 0002 [#1] PREEMPT SMP > Call Trace: > [<ffffffff8168b902>] ? dwc3_trace+0x52/0x60 > [<ffffffff810c504d>] ? get_parent_ip+0xd/0x50 > [<ffffffff8171159c>] android_setup+0xbc/0x140 > [<ffffffff810ec190>] ? irq_finalize_oneshot+0xe0/0xe0 > [<ffffffff816917e7>] dwc3_ep0_delegate_req+0x37/0x50 > [<ffffffff81692e69>] dwc3_ep0_interrupt+0xaf9/0xc10 > [<ffffffff810c504d>] ? get_parent_ip+0xd/0x50 > [<ffffffff810ec190>] ? irq_finalize_oneshot+0xe0/0xe0 > [<ffffffff81690281>] dwc3_thread_interrupt+0x931/0xbf0 > [<ffffffff810ec190>] ? irq_finalize_oneshot+0xe0/0xe0 > [<ffffffff810ec1ae>] irq_thread_fn+0x1e/0x40 > [<ffffffff810ec674>] irq_thread+0x134/0x1b0 > [<ffffffff810ec260>] ? wake_threads_waitq+0x30/0x30 > [<ffffffff810b802d>] kthread+0xed/0x110 > [<ffffffff81a2fd6f>] ret_from_fork+0x3f/0x70 > RIP [<ffffffff8170e19d>] composite_setup+0x3d/0x1830 > > the root cause is dwc interrupt comes after usb_gadget_remove_driver. > the fix is stop udc to have the dwc3 disable the interrupt, then release > the resource in udc->driver->unbind. > usb_gadget_udc_stop--> > udc->gadget->ops->udc_stop(udc->gadget)--> > dwc3_gadget_stop > > Signed-off-by: he, bo <bo.he@xxxxxxxxx> > --- > drivers/usb/gadget/udc/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c > index e6f04ee..67e9aa5 100644 > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -1258,8 +1258,8 @@ static void usb_gadget_remove_driver(struct usb_udc *udc) > > usb_gadget_disconnect(udc->gadget); > udc->driver->disconnect(udc->gadget); > - udc->driver->unbind(udc->gadget); > usb_gadget_udc_stop(udc); > + udc->driver->unbind(udc->gadget); unbind must be called before udc_stop. This seems to be a bug *only* in dwc3. I can't see how this would happen, actually. On dwc3_gadget_stop() we mask dwc3's interrupts, so the handler should be executed anymore. Can you tell me how to reproduce this? I could try this out tomorrow. Which kernel are you using? I wonder if this is something caused by the Android patches. -- balbi -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
