[kbuild-all] Re: [kbuild] drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we previously assumed '_ep->desc' could be null (see line 1055)

Hi Dan On Tuesday, June 23, 2020 2:20 AM, Dan Carpenter wrote: <snip> > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp(a)intel.com&gt; > Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; > > New smatch warnings: > drivers/usb/gadget/udc/fsl_udc_core.c:1055 fsl_ep_fifo_status() error: we > previously assumed '_ep->desc' could be null (see line 1055) > <snip> > > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1047 static int fsl_ep_fifo_status(struct usb_ep *_ep) > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1048 { > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1049 struct fsl_ep *ep; > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1050 struct fsl_udc *udc; > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1051 int size = 0; > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1052 u32 bitmask; > 6414e94c203d92 drivers/usb/gadget/fsl_udc_core.c Li Yang > 2011-11-23 1053 struct ep_queue_head *qh; > 2ea6698d7b9266 drivers/usb/gadget/fsl_udc_core.c Anatolij Gustschin > 2011-04-18 1054 > 75eaa498c99eeb drivers/usb/gadget/udc/fsl_udc_core.c Nikhil Badola > 2019-10-21 @1055 if (!_ep || _ep->desc || !(_ep->desc->bEndpointAddress&0xF)) > ^^^^^^^^^ Reversed NULL test. This will always return -ENODEV. (Or possibly crash. But I suspect it always returns -ENODEV instead of crashing). So the kernel test reports warning in case of '_ep->desc is null', right? My understanding is that this judgement would return -ENODEV when executing '... || _ep-desc ||..' and never execute '_ep->desc->bEndpointAddress' part, so crash would not happen, am I right?