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