Re: [PATCH v3 1/3] usb: core: hcd: Add support for deferring roothub registration

[kernel test robot <lkp@intel.com>]

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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 <lkp@intel.com>

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

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