include/asm-generic/qspinlock.h:94:9: sparse: sparse: context imbalance in 'linflex_console_write' - unexpected unlock

From: kernel test robot
Date: Wed Sep 02 2020 - 08:12:21 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 9c7d619be5a002ea29c172df5e3c1227c22cbb41
commit: 09864c1cdf5c537bd01bff45181406e422ea988c tty: serial: Add linflexuart driver for S32V234
date: 12 months ago
config: arm64-randconfig-s031-20200902 (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 09864c1cdf5c537bd01bff45181406e422ea988c
# 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@xxxxxxxxx>


sparse warnings: (new ones prefixed by >>)

drivers/tty/serial/fsl_linflexuart.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 'linflex_console_write' - unexpected unlock

# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=09864c1cdf5c537bd01bff45181406e422ea988c
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 09864c1cdf5c537bd01bff45181406e422ea988c
vim +/linflex_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@xxxxxxx>
:::::: CC: Ingo Molnar <mingo@xxxxxxxxxx>

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

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