diff mbox series

[v7,2/2] usb: gadget: udc: core: Prevent soft_connect_store() race

Message ID 20230608204517.105396-2-badhri@google.com
State New
Headers
Series [v7,1/2] usb: gadget: udc: core: Offload usb_udc_vbus_handler processing |

Commit Message

Badhri Jagan Sridharan June 8, 2023, 8:45 p.m. UTC 
  usb_udc_connect_control(), soft_connect_store() and
usb_gadget_deactivate() can potentially race against each other to invoke
usb_gadget_connect()/usb_gadget_disconnect(). To prevent this, guard
udc->started, gadget->allow_connect, gadget->deactivate and
gadget->connect with connect_lock so that ->pullup() is only invoked when
the gadget is bound, started and not deactivated. The routines
usb_gadget_connect_locked(), usb_gadget_disconnect_locked(),
usb_udc_connect_control_locked(), usb_gadget_udc_start_locked(),
usb_gadget_udc_stop_locked() are called with this lock held.

An earlier version of this commit was reverted due to the crash reported in
https://lore.kernel.org/all/ZF4BvgsOyoKxdPFF@francesco-nb.int.toradex.com/.
commit 16737e78d190 ("usb: gadget: udc: core: Offload usb_udc_vbus_handler processing")
addresses the crash reported.

Cc: stable@vger.kernel.org
Fixes: 628ef0d273a6 ("usb: udc: add usb_udc_vbus_handler")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
v5 is the first version in this series.
Changes since v5:
** Fixed up commit message
** Wrapped comments at 76.

Changes since v6:
** Address Alan comments around style/presentation.
** Fixed code to acquire ->connect_lock before testing gadget->deactivated.
---
 drivers/usb/gadget/udc/core.c | 153 +++++++++++++++++++++++-----------
 1 file changed, 106 insertions(+), 47 deletions(-)

Comments

kernel test robot June 8, 2023, 11:18 p.m. UTC | #1 
Hi Badhri,

kernel test robot noticed the following build warnings:

[auto build test WARNING on d37537a1f7cf09e304fe7993cb5e732534a0fb22]

url:    https://github.com/intel-lab-lkp/linux/commits/Badhri-Jagan-Sridharan/usb-gadget-udc-core-Prevent-soft_connect_store-race/20230609-044555
base:   d37537a1f7cf09e304fe7993cb5e732534a0fb22
patch link:    https://lore.kernel.org/r/20230608204517.105396-2-badhri%40google.com
patch subject: [PATCH v7 2/2] usb: gadget: udc: core: Prevent soft_connect_store() race
config: hexagon-randconfig-r015-20230608 (https://download.01.org/0day-ci/archive/20230609/202306090722.opxFRfOO-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout d37537a1f7cf09e304fe7993cb5e732534a0fb22
        b4 shazam https://lore.kernel.org/r/20230608204517.105396-2-badhri@google.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/usb/gadget/udc/

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306090722.opxFRfOO-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/usb/gadget/udc/core.c:17:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/usb/gadget/udc/core.c:17:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/usb/gadget/udc/core.c:17:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> drivers/usb/gadget/udc/core.c:850:1: warning: unused label 'out' [-Wunused-label]
     850 | out:
         | ^~~~
     851 |         trace_usb_gadget_deactivate(gadget, ret);
   drivers/usb/gadget/udc/core.c:886:1: warning: unused label 'out' [-Wunused-label]
     886 | out:
         | ^~~~
     887 |         trace_usb_gadget_activate(gadget, ret);
   8 warnings generated.


vim +/out +850 drivers/usb/gadget/udc/core.c

5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  815  
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  816  /**
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  817   * usb_gadget_deactivate - deactivate function which is not ready to work
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  818   * @gadget: the peripheral being deactivated
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  819   *
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  820   * This routine may be used during the gadget driver bind() call to prevent
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  821   * the peripheral from ever being visible to the USB host, unless later
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  822   * usb_gadget_activate() is called.  For example, user mode components may
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  823   * need to be activated before the system can talk to hosts.
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  824   *
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  825   * Returns zero on success, else negative errno.
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  826   */
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  827  int usb_gadget_deactivate(struct usb_gadget *gadget)
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  828  {
5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  829  	int ret = 0;
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  830  
bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  831  	mutex_lock(&gadget->udc->connect_lock);
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  832  	if (gadget->deactivated)
bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  833  		goto unlock;
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  834  
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  835  	if (gadget->connected) {
bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  836  		ret = usb_gadget_disconnect_locked(gadget);
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  837  		if (ret)
bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  838  			goto unlock;
5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  839  
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  840  		/*
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  841  		 * If gadget was being connected before deactivation, we want
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  842  		 * to reconnect it in usb_gadget_activate().
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  843  		 */
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  844  		gadget->connected = true;
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  845  	}
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  846  	gadget->deactivated = true;
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  847  
bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  848  unlock:
bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  849  	mutex_unlock(&gadget->udc->connect_lock);
5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31 @850  out:
5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  851  	trace_usb_gadget_deactivate(gadget, ret);
5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  852  
5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  853  	return ret;
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  854  }
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  855  EXPORT_SYMBOL_GPL(usb_gadget_deactivate);
5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  856
Badhri Jagan Sridharan June 9, 2023, 1:10 a.m. UTC | #2 
Removed the unused out labels reported by test in v8.

Regards,
Badhri

On Thu, Jun 8, 2023 at 4:20 PM kernel test robot <lkp@intel.com> wrote:
>
> Hi Badhri,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on d37537a1f7cf09e304fe7993cb5e732534a0fb22]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Badhri-Jagan-Sridharan/usb-gadget-udc-core-Prevent-soft_connect_store-race/20230609-044555
> base:   d37537a1f7cf09e304fe7993cb5e732534a0fb22
> patch link:    https://lore.kernel.org/r/20230608204517.105396-2-badhri%40google.com
> patch subject: [PATCH v7 2/2] usb: gadget: udc: core: Prevent soft_connect_store() race
> config: hexagon-randconfig-r015-20230608 (https://download.01.org/0day-ci/archive/20230609/202306090722.opxFRfOO-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
> reproduce (this is a W=1 build):
>         mkdir -p ~/bin
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         git checkout d37537a1f7cf09e304fe7993cb5e732534a0fb22
>         b4 shazam https://lore.kernel.org/r/20230608204517.105396-2-badhri@google.com
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/usb/gadget/udc/
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202306090722.opxFRfOO-lkp@intel.com/
>
> All warnings (new ones prefixed by >>):
>
>    In file included from drivers/usb/gadget/udc/core.c:17:
>    In file included from include/linux/dma-mapping.h:10:
>    In file included from include/linux/scatterlist.h:9:
>    In file included from arch/hexagon/include/asm/io.h:334:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      547 |         val = __raw_readb(PCI_IOBASE + addr);
>          |                           ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
>          |                                                         ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
>       37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>          |                                                   ^
>    In file included from drivers/usb/gadget/udc/core.c:17:
>    In file included from include/linux/dma-mapping.h:10:
>    In file included from include/linux/scatterlist.h:9:
>    In file included from arch/hexagon/include/asm/io.h:334:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
>          |                                                         ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
>       35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>          |                                                   ^
>    In file included from drivers/usb/gadget/udc/core.c:17:
>    In file included from include/linux/dma-mapping.h:10:
>    In file included from include/linux/scatterlist.h:9:
>    In file included from arch/hexagon/include/asm/io.h:334:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      584 |         __raw_writeb(value, PCI_IOBASE + addr);
>          |                             ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
>          |                                                       ~~~~~~~~~~ ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
>          |                                                       ~~~~~~~~~~ ^
> >> drivers/usb/gadget/udc/core.c:850:1: warning: unused label 'out' [-Wunused-label]
>      850 | out:
>          | ^~~~
>      851 |         trace_usb_gadget_deactivate(gadget, ret);
>    drivers/usb/gadget/udc/core.c:886:1: warning: unused label 'out' [-Wunused-label]
>      886 | out:
>          | ^~~~
>      887 |         trace_usb_gadget_activate(gadget, ret);
>    8 warnings generated.
>
>
> vim +/out +850 drivers/usb/gadget/udc/core.c
>
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  815
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  816  /**
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  817   * usb_gadget_deactivate - deactivate function which is not ready to work
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  818   * @gadget: the peripheral being deactivated
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  819   *
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  820   * This routine may be used during the gadget driver bind() call to prevent
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  821   * the peripheral from ever being visible to the USB host, unless later
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  822   * usb_gadget_activate() is called.  For example, user mode components may
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  823   * need to be activated before the system can talk to hosts.
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  824   *
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  825   * Returns zero on success, else negative errno.
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  826   */
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  827  int usb_gadget_deactivate(struct usb_gadget *gadget)
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  828  {
> 5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  829         int ret = 0;
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  830
> bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  831         mutex_lock(&gadget->udc->connect_lock);
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  832         if (gadget->deactivated)
> bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  833                 goto unlock;
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  834
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  835         if (gadget->connected) {
> bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  836                 ret = usb_gadget_disconnect_locked(gadget);
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  837                 if (ret)
> bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  838                         goto unlock;
> 5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  839
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  840                 /*
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  841                  * If gadget was being connected before deactivation, we want
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  842                  * to reconnect it in usb_gadget_activate().
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  843                  */
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  844                 gadget->connected = true;
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  845         }
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  846         gadget->deactivated = true;
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  847
> bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  848  unlock:
> bfc8a68e3289a9 drivers/usb/gadget/udc/core.c     Badhri Jagan Sridharan 2023-06-08  849         mutex_unlock(&gadget->udc->connect_lock);
> 5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31 @850  out:
> 5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  851         trace_usb_gadget_deactivate(gadget, ret);
> 5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  852
> 5e42d710a108c2 drivers/usb/gadget/udc/core.c     Felipe Balbi           2016-05-31  853         return ret;
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  854  }
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  855  EXPORT_SYMBOL_GPL(usb_gadget_deactivate);
> 5a8d651a2bde01 drivers/usb/gadget/udc/udc-core.c Felipe Balbi           2016-05-31  856
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
diff mbox series

Patch

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index d2e4f78c53e3..2549717c1446 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -40,6 +40,11 @@  static const struct bus_type gadget_bus_type;
  * @allow_connect: Indicates whether UDC is allowed to be pulled up.
  * Set/cleared by gadget_(un)bind_driver() after gadget driver is bound or
  * unbound.
+ * @connect_lock: protects udc->started, gadget->connect,
+ * gadget->allow_connect and gadget->deactivate. The routines
+ * usb_gadget_connect_locked(), usb_gadget_disconnect_locked(),
+ * usb_udc_connect_control_locked(), usb_gadget_udc_start_locked() and
+ * usb_gadget_udc_stop_locked() are called with this lock held.
  *
  * This represents the internal data structure which is used by the UDC-class
  * to hold information about udc driver and gadget together.
@@ -53,6 +58,7 @@  struct usb_udc {
 	bool				started;
 	bool				allow_connect;
 	struct work_struct		vbus_work;
+	struct mutex			connect_lock;
 };
 
 static struct class *udc_class;
@@ -692,17 +698,8 @@  int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
 }
 EXPORT_SYMBOL_GPL(usb_gadget_vbus_disconnect);
 
-/**
- * usb_gadget_connect - software-controlled connect to USB host
- * @gadget:the peripheral being connected
- *
- * Enables the D+ (or potentially D-) pullup.  The host will start
- * enumerating this gadget when the pullup is active and a VBUS session
- * is active (the link is powered).
- *
- * Returns zero on success, else negative errno.
- */
-int usb_gadget_connect(struct usb_gadget *gadget)
+static int usb_gadget_connect_locked(struct usb_gadget *gadget)
+	__must_hold(&gadget->udc->connect_lock)
 {
 	int ret = 0;
 
@@ -711,10 +708,12 @@  int usb_gadget_connect(struct usb_gadget *gadget)
 		goto out;
 	}
 
-	if (gadget->deactivated || !gadget->udc->allow_connect) {
+	if (gadget->deactivated || !gadget->udc->allow_connect || !gadget->udc->started) {
 		/*
-		 * If gadget is deactivated we only save new state.
-		 * Gadget will be connected automatically after activation.
+		 * If the gadget isn't usable (because it is deactivated,
+		 * unbound, or not yet started), we only save the new state.
+		 * The gadget will be connected automatically when it is
+		 * activated/bound/started.
 		 */
 		gadget->connected = true;
 		goto out;
@@ -729,22 +728,31 @@  int usb_gadget_connect(struct usb_gadget *gadget)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(usb_gadget_connect);
 
 /**
- * usb_gadget_disconnect - software-controlled disconnect from USB host
- * @gadget:the peripheral being disconnected
- *
- * Disables the D+ (or potentially D-) pullup, which the host may see
- * as a disconnect (when a VBUS session is active).  Not all systems
- * support software pullup controls.
+ * usb_gadget_connect - software-controlled connect to USB host
+ * @gadget:the peripheral being connected
  *
- * Following a successful disconnect, invoke the ->disconnect() callback
- * for the current gadget driver so that UDC drivers don't need to.
+ * Enables the D+ (or potentially D-) pullup.  The host will start
+ * enumerating this gadget when the pullup is active and a VBUS session
+ * is active (the link is powered).
  *
  * Returns zero on success, else negative errno.
  */
-int usb_gadget_disconnect(struct usb_gadget *gadget)
+int usb_gadget_connect(struct usb_gadget *gadget)
+{
+	int ret;
+
+	mutex_lock(&gadget->udc->connect_lock);
+	ret = usb_gadget_connect_locked(gadget);
+	mutex_unlock(&gadget->udc->connect_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_connect);
+
+static int usb_gadget_disconnect_locked(struct usb_gadget *gadget)
+	__must_hold(&gadget->udc->connect_lock)
 {
 	int ret = 0;
 
@@ -756,7 +764,7 @@  int usb_gadget_disconnect(struct usb_gadget *gadget)
 	if (!gadget->connected)
 		goto out;
 
-	if (gadget->deactivated) {
+	if (gadget->deactivated || !gadget->udc->started) {
 		/*
 		 * If gadget is deactivated we only save new state.
 		 * Gadget will stay disconnected after activation.
@@ -779,6 +787,30 @@  int usb_gadget_disconnect(struct usb_gadget *gadget)
 
 	return ret;
 }
+
+/**
+ * usb_gadget_disconnect - software-controlled disconnect from USB host
+ * @gadget:the peripheral being disconnected
+ *
+ * Disables the D+ (or potentially D-) pullup, which the host may see
+ * as a disconnect (when a VBUS session is active).  Not all systems
+ * support software pullup controls.
+ *
+ * Following a successful disconnect, invoke the ->disconnect() callback
+ * for the current gadget driver so that UDC drivers don't need to.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_disconnect(struct usb_gadget *gadget)
+{
+	int ret;
+
+	mutex_lock(&gadget->udc->connect_lock);
+	ret = usb_gadget_disconnect_locked(gadget);
+	mutex_unlock(&gadget->udc->connect_lock);
+
+	return ret;
+}
 EXPORT_SYMBOL_GPL(usb_gadget_disconnect);
 
 /**
@@ -796,13 +828,14 @@  int usb_gadget_deactivate(struct usb_gadget *gadget)
 {
 	int ret = 0;
 
+	mutex_lock(&gadget->udc->connect_lock);
 	if (gadget->deactivated)
-		goto out;
+		goto unlock;
 
 	if (gadget->connected) {
-		ret = usb_gadget_disconnect(gadget);
+		ret = usb_gadget_disconnect_locked(gadget);
 		if (ret)
-			goto out;
+			goto unlock;
 
 		/*
 		 * If gadget was being connected before deactivation, we want
@@ -812,6 +845,8 @@  int usb_gadget_deactivate(struct usb_gadget *gadget)
 	}
 	gadget->deactivated = true;
 
+unlock:
+	mutex_unlock(&gadget->udc->connect_lock);
 out:
 	trace_usb_gadget_deactivate(gadget, ret);
 
@@ -832,8 +867,9 @@  int usb_gadget_activate(struct usb_gadget *gadget)
 {
 	int ret = 0;
 
+	mutex_lock(&gadget->udc->connect_lock);
 	if (!gadget->deactivated)
-		goto out;
+		goto unlock;
 
 	gadget->deactivated = false;
 
@@ -842,8 +878,11 @@  int usb_gadget_activate(struct usb_gadget *gadget)
 	 * while it was being deactivated, we call usb_gadget_connect().
 	 */
 	if (gadget->connected)
-		ret = usb_gadget_connect(gadget);
+		ret = usb_gadget_connect_locked(gadget);
+	mutex_unlock(&gadget->udc->connect_lock);
 
+unlock:
+	mutex_unlock(&gadget->udc->connect_lock);
 out:
 	trace_usb_gadget_activate(gadget, ret);
 
@@ -1083,19 +1122,22 @@  EXPORT_SYMBOL_GPL(usb_gadget_set_state);
 
 /* ------------------------------------------------------------------------- */
 
-static void usb_udc_connect_control(struct usb_udc *udc)
+/* Acquire connect_lock before calling this function. */
+static void usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock)
 {
 	if (udc->vbus)
-		usb_gadget_connect(udc->gadget);
+		usb_gadget_connect_locked(udc->gadget);
 	else
-		usb_gadget_disconnect(udc->gadget);
+		usb_gadget_disconnect_locked(udc->gadget);
 }
 
 static void vbus_event_work(struct work_struct *work)
 {
 	struct usb_udc *udc = container_of(work, struct usb_udc, vbus_work);
 
-	usb_udc_connect_control(udc);
+	mutex_lock(&udc->connect_lock);
+	usb_udc_connect_control_locked(udc);
+	mutex_unlock(&udc->connect_lock);
 }
 
 /**
@@ -1144,7 +1186,7 @@  void usb_gadget_udc_reset(struct usb_gadget *gadget,
 EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
 
 /**
- * usb_gadget_udc_start - tells usb device controller to start up
+ * usb_gadget_udc_start_locked - tells usb device controller to start up
  * @udc: The UDC to be started
  *
  * This call is issued by the UDC Class driver when it's about
@@ -1155,8 +1197,11 @@  EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
  * necessary to have it powered on.
  *
  * Returns zero on success, else negative errno.
+ *
+ * Caller should acquire connect_lock before invoking this function.
  */
-static inline int usb_gadget_udc_start(struct usb_udc *udc)
+static inline int usb_gadget_udc_start_locked(struct usb_udc *udc)
+	__must_hold(&udc->connect_lock)
 {
 	int ret;
 
@@ -1173,7 +1218,7 @@  static inline int usb_gadget_udc_start(struct usb_udc *udc)
 }
 
 /**
- * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
+ * usb_gadget_udc_stop_locked - tells usb device controller we don't need it anymore
  * @udc: The UDC to be stopped
  *
  * This call is issued by the UDC Class driver after calling
@@ -1182,8 +1227,11 @@  static inline int usb_gadget_udc_start(struct usb_udc *udc)
  * The details are implementation specific, but it can go as
  * far as powering off UDC completely and disable its data
  * line pullups.
+ *
+ * Caller should acquire connect lock before invoking this function.
  */
-static inline void usb_gadget_udc_stop(struct usb_udc *udc)
+static inline void usb_gadget_udc_stop_locked(struct usb_udc *udc)
+	__must_hold(&udc->connect_lock)
 {
 	if (!udc->started) {
 		dev_err(&udc->dev, "UDC had already stopped\n");
@@ -1342,6 +1390,7 @@  int usb_add_gadget(struct usb_gadget *gadget)
 
 	udc->gadget = gadget;
 	gadget->udc = udc;
+	mutex_init(&udc->connect_lock);
 
 	udc->started = false;
 
@@ -1545,12 +1594,16 @@  static int gadget_bind_driver(struct device *dev)
 	if (ret)
 		goto err_bind;
 
-	ret = usb_gadget_udc_start(udc);
-	if (ret)
+	mutex_lock(&udc->connect_lock);
+	ret = usb_gadget_udc_start_locked(udc);
+	if (ret) {
+		mutex_unlock(&udc->connect_lock);
 		goto err_start;
+	}
 	usb_gadget_enable_async_callbacks(udc);
 	udc->allow_connect = true;
-	usb_udc_connect_control(udc);
+	usb_udc_connect_control_locked(udc);
+	mutex_unlock(&udc->connect_lock);
 
 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 	return 0;
@@ -1583,12 +1636,14 @@  static void gadget_unbind_driver(struct device *dev)
 
 	udc->allow_connect = false;
 	cancel_work_sync(&udc->vbus_work);
-	usb_gadget_disconnect(gadget);
+	mutex_lock(&udc->connect_lock);
+	usb_gadget_disconnect_locked(gadget);
 	usb_gadget_disable_async_callbacks(udc);
 	if (gadget->irq)
 		synchronize_irq(gadget->irq);
 	udc->driver->unbind(gadget);
-	usb_gadget_udc_stop(udc);
+	usb_gadget_udc_stop_locked(udc);
+	mutex_unlock(&udc->connect_lock);
 
 	mutex_lock(&udc_lock);
 	driver->is_bound = false;
@@ -1674,11 +1729,15 @@  static ssize_t soft_connect_store(struct device *dev,
 	}
 
 	if (sysfs_streq(buf, "connect")) {
-		usb_gadget_udc_start(udc);
-		usb_gadget_connect(udc->gadget);
+		mutex_lock(&udc->connect_lock);
+		usb_gadget_udc_start_locked(udc);
+		usb_gadget_connect_locked(udc->gadget);
+		mutex_unlock(&udc->connect_lock);
 	} else if (sysfs_streq(buf, "disconnect")) {
-		usb_gadget_disconnect(udc->gadget);
-		usb_gadget_udc_stop(udc);
+		mutex_lock(&udc->connect_lock);
+		usb_gadget_disconnect_locked(udc->gadget);
+		usb_gadget_udc_stop_locked(udc);
+		mutex_unlock(&udc->connect_lock);
 	} else {
 		dev_err(dev, "unsupported command '%s'\n", buf);
 		ret = -EINVAL;