Hi Kishon, I love your patch! Perhaps something to improve: [auto build test WARNING on usb/usb-testing] [also build test WARNING on v5.14 next-20210908] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Kishon-Vijay-Abraham-I/Fix-cold-plugged-USB-device-on-certain-PCIe-USB-cards/20210908-175547 base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing config: riscv-randconfig-r012-20210908 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 9c476172b93367d2cb88d7d3f4b1b5b456fa6020) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://github.com/0day-ci/linux/commit/03e83cc595ea0a47e7f25c7d7b541d704b06932c git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Kishon-Vijay-Abraham-I/Fix-cold-plugged-USB-device-on-certain-PCIe-USB-cards/20210908-175547 git checkout 03e83cc595ea0a47e7f25c7d7b541d704b06932c # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from drivers/usb/core/hcd.c:21: In file included from arch/riscv/include/asm/io.h:136: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from drivers/usb/core/hcd.c:21: In file included from arch/riscv/include/asm/io.h:136: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from drivers/usb/core/hcd.c:21: In file included from arch/riscv/include/asm/io.h:136: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:1024:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port; ~~~~~~~~~~ ^ >> drivers/usb/core/hcd.c:3013:6: warning: variable 'rh_registered' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (hcd->rh_registered == 1) ^~~~~~~~~~~~~~~~~~~~~~~ drivers/usb/core/hcd.c:3024:6: note: uninitialized use occurs here if (rh_registered == 1) ^~~~~~~~~~~~~ drivers/usb/core/hcd.c:3013:2: note: remove the 'if' if its condition is always true if (hcd->rh_registered == 1) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/usb/core/hcd.c:3002:24: note: initialize the variable 'rh_registered' to silence this warning unsigned rh_registered; ^ = 0 8 warnings generated. vim +3013 drivers/usb/core/hcd.c 2989 2990 /** 2991 * usb_remove_hcd - shutdown processing for generic HCDs 2992 * @hcd: the usb_hcd structure to remove 2993 * 2994 * Context: task context, might sleep. 2995 * 2996 * Disconnects the root hub, then reverses the effects of usb_add_hcd(), 2997 * invoking the HCD's stop() method. 2998 */ 2999 void usb_remove_hcd(struct usb_hcd *hcd) 3000 { 3001 struct usb_device *rhdev = hcd->self.root_hub; 3002 unsigned rh_registered; 3003 3004 dev_info(hcd->self.controller, "remove, state %x\n", hcd->state); 3005 3006 usb_get_dev(rhdev); 3007 clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags); 3008 if (HC_IS_RUNNING (hcd->state)) 3009 hcd->state = HC_STATE_QUIESCING; 3010 3011 dev_dbg(hcd->self.controller, "roothub graceful disconnect\n"); 3012 spin_lock_irq (&hcd_root_hub_lock); > 3013 if (hcd->rh_registered == 1) 3014 rh_registered = 1; 3015 hcd->rh_registered = 0; 3016 spin_unlock_irq (&hcd_root_hub_lock); 3017 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org