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* include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock
@ 2020-08-29  0:27 kernel test robot
  2020-08-31  0:46 ` Leo Yan
  0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2020-08-29  0:27 UTC (permalink / raw)
  To: Leo Yan; +Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman, Jeffrey Hugo

[-- Attachment #1: Type: text/plain, Size: 3339 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   005c53447a63cbce10de37406975a34d7bdc8704
commit: 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e tty: serial: msm_serial: Fix lockup for sysrq and oops
date:   9 months ago
config: arm64-randconfig-s031-20200829 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.2-191-g10164920-dirty
        git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

   drivers/tty/serial/msm_serial.c:736:25: sparse: sparse: context imbalance in 'msm_handle_rx_dm' - unexpected unlock
   drivers/tty/serial/msm_serial.c:802:28: sparse: sparse: context imbalance in 'msm_handle_rx' - unexpected unlock
   drivers/tty/serial/msm_serial.c:1100:12: sparse: sparse: context imbalance in 'msm_set_baud_rate' - unexpected unlock
   drivers/tty/serial/msm_serial.c: note: in included file (through arch/arm64/include/generated/asm/qspinlock.h, arch/arm64/include/asm/spinlock.h, include/linux/spinlock.h, ...):
>> include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock

# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
vim +/__msm_console_write +94 include/asm-generic/qspinlock.h

a33fda35e3a765 Waiman Long 2015-04-24  83  
a33fda35e3a765 Waiman Long 2015-04-24  84  #ifndef queued_spin_unlock
a33fda35e3a765 Waiman Long 2015-04-24  85  /**
a33fda35e3a765 Waiman Long 2015-04-24  86   * queued_spin_unlock - release a queued spinlock
a33fda35e3a765 Waiman Long 2015-04-24  87   * @lock : Pointer to queued spinlock structure
a33fda35e3a765 Waiman Long 2015-04-24  88   */
a33fda35e3a765 Waiman Long 2015-04-24  89  static __always_inline void queued_spin_unlock(struct qspinlock *lock)
a33fda35e3a765 Waiman Long 2015-04-24  90  {
a33fda35e3a765 Waiman Long 2015-04-24  91  	/*
ca50e426f96c90 Pan Xinhui  2016-06-03  92  	 * unlock() needs release semantics:
a33fda35e3a765 Waiman Long 2015-04-24  93  	 */
626e5fbc143589 Will Deacon 2018-04-26 @94  	smp_store_release(&lock->locked, 0);
a33fda35e3a765 Waiman Long 2015-04-24  95  }
a33fda35e3a765 Waiman Long 2015-04-24  96  #endif
a33fda35e3a765 Waiman Long 2015-04-24  97  

:::::: The code at line 94 was first introduced by commit
:::::: 626e5fbc14358901ddaa90ce510e0fbeab310432 locking/qspinlock: Use smp_store_release() in queued_spin_unlock()

:::::: TO: Will Deacon <will.deacon@arm.com>
:::::: CC: Ingo Molnar <mingo@kernel.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 39362 bytes --]

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock
  2020-08-29  0:27 include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock kernel test robot
@ 2020-08-31  0:46 ` Leo Yan
  2020-09-02  8:07   ` [kbuild-all] " Xia, Hui
  0 siblings, 1 reply; 4+ messages in thread
From: Leo Yan @ 2020-08-31  0:46 UTC (permalink / raw)
  To: kernel test robot
  Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman, Jeffrey Hugo

Hi,

On Sat, Aug 29, 2020 at 08:27:03AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   005c53447a63cbce10de37406975a34d7bdc8704
> commit: 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e tty: serial: msm_serial: Fix lockup for sysrq and oops
> date:   9 months ago
> config: arm64-randconfig-s031-20200829 (attached as .config)
> compiler: aarch64-linux-gcc (GCC) 9.3.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # apt-get install sparse
>         # sparse version: v0.6.2-191-g10164920-dirty
>         git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> 
> sparse warnings: (new ones prefixed by >>)
> 
>    drivers/tty/serial/msm_serial.c:736:25: sparse: sparse: context imbalance in 'msm_handle_rx_dm' - unexpected unlock
>    drivers/tty/serial/msm_serial.c:802:28: sparse: sparse: context imbalance in 'msm_handle_rx' - unexpected unlock
>    drivers/tty/serial/msm_serial.c:1100:12: sparse: sparse: context imbalance in 'msm_set_baud_rate' - unexpected unlock
>    drivers/tty/serial/msm_serial.c: note: in included file (through arch/arm64/include/generated/asm/qspinlock.h, arch/arm64/include/asm/spinlock.h, include/linux/spinlock.h, ...):
> >> include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock

I think this is a false positive report.  Let's see the locking
relevant code in __msm_console_write():

  __msm_console_write() {

      int locked = 1;

      [...]

      if (port->sysrq)
          locked = 0;
      else if (oops_in_progress)
          locked = spin_trylock(&port->lock);
      else
          spin_lock(&port->lock);

      [...]

      if (locked)
          spin_unlock(&port->lock);
  }

Since we need to handle oops and sysrq as special cases, it uses
'locked' to indicate the spinlock has been acquired and later will
release spinlock if 'locked' is true.  So locking and unlocking are
paired and I don't see what's the reason the robot reports the context
imbalance.

BTW, this report is not only for msm_serial driver, it also might be
applied to many other serial drivers, e.g.

  drivers/tty/serial/amba-pl011.c
  drivers/tty/serial/xilinx_uartps.c
  drivers/tty/serial/stm32-usart.c

Maybe I miss something at here, if so please let me know.

Thanks,
Leo

> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
> vim +/__msm_console_write +94 include/asm-generic/qspinlock.h
> 
> a33fda35e3a765 Waiman Long 2015-04-24  83  
> a33fda35e3a765 Waiman Long 2015-04-24  84  #ifndef queued_spin_unlock
> a33fda35e3a765 Waiman Long 2015-04-24  85  /**
> a33fda35e3a765 Waiman Long 2015-04-24  86   * queued_spin_unlock - release a queued spinlock
> a33fda35e3a765 Waiman Long 2015-04-24  87   * @lock : Pointer to queued spinlock structure
> a33fda35e3a765 Waiman Long 2015-04-24  88   */
> a33fda35e3a765 Waiman Long 2015-04-24  89  static __always_inline void queued_spin_unlock(struct qspinlock *lock)
> a33fda35e3a765 Waiman Long 2015-04-24  90  {
> a33fda35e3a765 Waiman Long 2015-04-24  91  	/*
> ca50e426f96c90 Pan Xinhui  2016-06-03  92  	 * unlock() needs release semantics:
> a33fda35e3a765 Waiman Long 2015-04-24  93  	 */
> 626e5fbc143589 Will Deacon 2018-04-26 @94  	smp_store_release(&lock->locked, 0);
> a33fda35e3a765 Waiman Long 2015-04-24  95  }
> a33fda35e3a765 Waiman Long 2015-04-24  96  #endif
> a33fda35e3a765 Waiman Long 2015-04-24  97  
> 
> :::::: The code at line 94 was first introduced by commit
> :::::: 626e5fbc14358901ddaa90ce510e0fbeab310432 locking/qspinlock: Use smp_store_release() in queued_spin_unlock()
> 
> :::::: TO: Will Deacon <will.deacon@arm.com>
> :::::: CC: Ingo Molnar <mingo@kernel.org>
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org



^ permalink raw reply	[flat|nested] 4+ messages in thread
* RE: [kbuild-all] Re: include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock
  2020-08-31  0:46 ` Leo Yan
@ 2020-09-02  8:07   ` Xia, Hui
  0 siblings, 0 replies; 4+ messages in thread
From: Xia, Hui @ 2020-09-02  8:07 UTC (permalink / raw)
  To: Leo Yan, lkp; +Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman, Jeffrey Hugo



>-----Original Message-----
>From: Leo Yan <leo.yan@linaro.org>
>Sent: 2020年8月31日 8:47
>To: lkp <lkp@intel.com>
>Cc: kbuild-all@lists.01.org; linux-kernel@vger.kernel.org; Greg Kroah-Hartman
><gregkh@linuxfoundation.org>; Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
>Subject: [kbuild-all] Re: include/asm-generic/qspinlock.h:94:9: sparse: sparse:
>context imbalance in '__msm_console_write' - unexpected unlock
>
>Hi,
>
>On Sat, Aug 29, 2020 at 08:27:03AM +0800, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   005c53447a63cbce10de37406975a34d7bdc8704
>> commit: 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e tty: serial: msm_serial:
>Fix lockup for sysrq and oops
>> date:   9 months ago
>> config: arm64-randconfig-s031-20200829 (attached as .config)
>> compiler: aarch64-linux-gcc (GCC) 9.3.0
>> reproduce:
>>         wget https://raw.githubusercontent.com/intel/lkp-
>tests/master/sbin/make.cross -O ~/bin/make.cross
>>         chmod +x ~/bin/make.cross
>>         # apt-get install sparse
>>         # sparse version: v0.6.2-191-g10164920-dirty
>>         git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
>>         # save the attached .config to linux build tree
>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross
>> C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>>
>> sparse warnings: (new ones prefixed by >>)
>>
>>    drivers/tty/serial/msm_serial.c:736:25: sparse: sparse: context imbalance in
>'msm_handle_rx_dm' - unexpected unlock
>>    drivers/tty/serial/msm_serial.c:802:28: sparse: sparse: context imbalance in
>'msm_handle_rx' - unexpected unlock
>>    drivers/tty/serial/msm_serial.c:1100:12: sparse: sparse: context imbalance in
>'msm_set_baud_rate' - unexpected unlock
>>    drivers/tty/serial/msm_serial.c: note: in included file (through
>arch/arm64/include/generated/asm/qspinlock.h,
>arch/arm64/include/asm/spinlock.h, include/linux/spinlock.h, ...):
>> >> include/asm-generic/qspinlock.h:94:9: sparse: sparse: context
>> >> imbalance in '__msm_console_write' - unexpected unlock
>
>I think this is a false positive report.  Let's see the locking relevant code in
>__msm_console_write():
Hi Yan,

Thanks for the clarification. Please ignore this report.
It was sent out unexpected. We will fix the robot bug soon.

Best Regards,
Hui
>
>  __msm_console_write() {
>
>      int locked = 1;
>
>      [...]
>
>      if (port->sysrq)
>          locked = 0;
>      else if (oops_in_progress)
>          locked = spin_trylock(&port->lock);
>      else
>          spin_lock(&port->lock);
>
>      [...]
>
>      if (locked)
>          spin_unlock(&port->lock);
>  }
>
>Since we need to handle oops and sysrq as special cases, it uses 'locked' to
>indicate the spinlock has been acquired and later will release spinlock if 'locked' is
>true.  So locking and unlocking are paired and I don't see what's the reason the
>robot reports the context imbalance.
>
>BTW, this report is not only for msm_serial driver, it also might be applied to
>many other serial drivers, e.g.
>
>  drivers/tty/serial/amba-pl011.c
>  drivers/tty/serial/xilinx_uartps.c
>  drivers/tty/serial/stm32-usart.c
>
>Maybe I miss something at here, if so please let me know.
>
>Thanks,
>Leo
>
>> #
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/com
>> mit/?id=0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
>> git remote add linus
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>> git fetch --no-tags linus master
>> git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
>> vim +/__msm_console_write +94 include/asm-generic/qspinlock.h
>>
>> a33fda35e3a765 Waiman Long 2015-04-24  83
>> a33fda35e3a765 Waiman Long 2015-04-24  84  #ifndef queued_spin_unlock
>> a33fda35e3a765 Waiman Long 2015-04-24  85  /**
>> a33fda35e3a765 Waiman Long 2015-04-24  86   * queued_spin_unlock - release
>a queued spinlock
>> a33fda35e3a765 Waiman Long 2015-04-24  87   * @lock : Pointer to queued
>spinlock structure
>> a33fda35e3a765 Waiman Long 2015-04-24  88   */
>> a33fda35e3a765 Waiman Long 2015-04-24  89  static __always_inline void
>> queued_spin_unlock(struct qspinlock *lock)
>> a33fda35e3a765 Waiman Long 2015-04-24  90  {
>> a33fda35e3a765 Waiman Long 2015-04-24  91  	/*
>> ca50e426f96c90 Pan Xinhui  2016-06-03  92  	 * unlock() needs release
>semantics:
>> a33fda35e3a765 Waiman Long 2015-04-24  93  	 */
>> 626e5fbc143589 Will Deacon 2018-04-26 @94
>	smp_store_release(&lock->locked, 0);
>> a33fda35e3a765 Waiman Long 2015-04-24  95  }
>> a33fda35e3a765 Waiman Long 2015-04-24  96  #endif
>> a33fda35e3a765 Waiman Long 2015-04-24  97
>>
>> :::::: The code at line 94 was first introduced by commit
>> :::::: 626e5fbc14358901ddaa90ce510e0fbeab310432 locking/qspinlock: Use
>> smp_store_release() in queued_spin_unlock()
>>
>> :::::: TO: Will Deacon <will.deacon@arm.com>
>> :::::: CC: Ingo Molnar <mingo@kernel.org>
>>
>> ---
>> 0-DAY CI Kernel Test Service, Intel Corporation
>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
>
>_______________________________________________
>kbuild-all mailing list -- kbuild-all@lists.01.org To unsubscribe send an email to
>kbuild-all-leave@lists.01.org

^ permalink raw reply	[flat|nested] 4+ messages in thread
* include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock
@ 2020-09-02  7:39 kernel test robot
  0 siblings, 0 replies; 4+ messages in thread
From: kernel test robot @ 2020-09-02  7:39 UTC (permalink / raw)
  To: Leo Yan; +Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman, Jeffrey Hugo

[-- Attachment #1: Type: text/plain, Size: 3339 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   9c7d619be5a002ea29c172df5e3c1227c22cbb41
commit: 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e tty: serial: msm_serial: Fix lockup for sysrq and oops
date:   9 months ago
config: arm64-randconfig-s031-20200829 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.2-191-g10164920-dirty
        git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

   drivers/tty/serial/msm_serial.c:736:25: sparse: sparse: context imbalance in 'msm_handle_rx_dm' - unexpected unlock
   drivers/tty/serial/msm_serial.c:802:28: sparse: sparse: context imbalance in 'msm_handle_rx' - unexpected unlock
   drivers/tty/serial/msm_serial.c:1100:12: sparse: sparse: context imbalance in 'msm_set_baud_rate' - unexpected unlock
   drivers/tty/serial/msm_serial.c: note: in included file (through arch/arm64/include/generated/asm/qspinlock.h, arch/arm64/include/asm/spinlock.h, include/linux/spinlock.h, ...):
>> include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock

# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 0e4f7f920a5c6bfe5e851e989f27b35a0cc7fb7e
vim +/__msm_console_write +94 include/asm-generic/qspinlock.h

a33fda35e3a765 Waiman Long 2015-04-24  83  
a33fda35e3a765 Waiman Long 2015-04-24  84  #ifndef queued_spin_unlock
a33fda35e3a765 Waiman Long 2015-04-24  85  /**
a33fda35e3a765 Waiman Long 2015-04-24  86   * queued_spin_unlock - release a queued spinlock
a33fda35e3a765 Waiman Long 2015-04-24  87   * @lock : Pointer to queued spinlock structure
a33fda35e3a765 Waiman Long 2015-04-24  88   */
a33fda35e3a765 Waiman Long 2015-04-24  89  static __always_inline void queued_spin_unlock(struct qspinlock *lock)
a33fda35e3a765 Waiman Long 2015-04-24  90  {
a33fda35e3a765 Waiman Long 2015-04-24  91  	/*
ca50e426f96c90 Pan Xinhui  2016-06-03  92  	 * unlock() needs release semantics:
a33fda35e3a765 Waiman Long 2015-04-24  93  	 */
626e5fbc143589 Will Deacon 2018-04-26 @94  	smp_store_release(&lock->locked, 0);
a33fda35e3a765 Waiman Long 2015-04-24  95  }
a33fda35e3a765 Waiman Long 2015-04-24  96  #endif
a33fda35e3a765 Waiman Long 2015-04-24  97  

:::::: The code at line 94 was first introduced by commit
:::::: 626e5fbc14358901ddaa90ce510e0fbeab310432 locking/qspinlock: Use smp_store_release() in queued_spin_unlock()

:::::: TO: Will Deacon <will.deacon@arm.com>
:::::: CC: Ingo Molnar <mingo@kernel.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 39362 bytes --]

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-09-02  8:08 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-29  0:27 include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in '__msm_console_write' - unexpected unlock kernel test robot
2020-08-31  0:46 ` Leo Yan
2020-09-02  8:07   ` [kbuild-all] " Xia, Hui
2020-09-02  7:39 kernel test robot

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