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| author |   Waiman Long <longman@redhat.com> | 2019-04-04 13:43:14 -0400 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2019-04-10 10:56:02 +0200 |
| commit | a68e2c4c637918da47b3aa270051545cff7d8245 (patch) | |
| tree | e028f26c238089d2e7588d47fa1360462d1d17fd /kernel/locking | |
| parent | locking/rwsem: Micro-optimize rwsem_try_read_lock_unqueued() (diff) | |
| download | linux-dev-a68e2c4c637918da47b3aa270051545cff7d8245.tar.xz linux-dev-a68e2c4c637918da47b3aa270051545cff7d8245.zip | |
locking/rwsem: Add debug check for __down_read*()
When rwsem_down_read_failed*() return, the read lock is acquired
indirectly by others. So debug checks are added in __down_read() and
__down_read_killable() to make sure the rwsem is really reader-owned.
The other debug check calls in kernel/locking/rwsem.c except the
one in up_read_non_owner() are also moved over to rwsem-xadd.h.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20190404174320.22416-6-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/rwsem.c | 3 | ||||
| -rw-r--r-- | kernel/locking/rwsem.h | 12 |
2 files changed, 10 insertions, 5 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 59e584895532..90de5f1780ba 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -109,7 +109,6 @@ EXPORT_SYMBOL(down_write_trylock); void up_read(struct rw_semaphore *sem) { rwsem_release(&sem->dep_map, 1, _RET_IP_); - DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED)); __up_read(sem); } @@ -122,7 +121,6 @@ EXPORT_SYMBOL(up_read); void up_write(struct rw_semaphore *sem) { rwsem_release(&sem->dep_map, 1, _RET_IP_); - DEBUG_RWSEMS_WARN_ON(sem->owner != current); __up_write(sem); } @@ -135,7 +133,6 @@ EXPORT_SYMBOL(up_write); void downgrade_write(struct rw_semaphore *sem) { lock_downgrade(&sem->dep_map, _RET_IP_); - DEBUG_RWSEMS_WARN_ON(sem->owner != current); __downgrade_write(sem); } diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h index 19997c82270b..1d8f722a6761 100644 --- a/kernel/locking/rwsem.h +++ b/kernel/locking/rwsem.h @@ -165,10 +165,13 @@ extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); */ static inline void __down_read(struct rw_semaphore *sem) { - if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) + if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) { rwsem_down_read_failed(sem); - else + DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & + RWSEM_READER_OWNED)); + } else { rwsem_set_reader_owned(sem); + } } static inline int __down_read_killable(struct rw_semaphore *sem) @@ -176,6 +179,8 @@ static inline int __down_read_killable(struct rw_semaphore *sem) if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) { if (IS_ERR(rwsem_down_read_failed_killable(sem))) return -EINTR; + DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & + RWSEM_READER_OWNED)); } else { rwsem_set_reader_owned(sem); } @@ -246,6 +251,7 @@ static inline void __up_read(struct rw_semaphore *sem) { long tmp; + DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED)); rwsem_clear_reader_owned(sem); tmp = atomic_long_dec_return_release(&sem->count); if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)) @@ -257,6 +263,7 @@ static inline void __up_read(struct rw_semaphore *sem) */ static inline void __up_write(struct rw_semaphore *sem) { + DEBUG_RWSEMS_WARN_ON(sem->owner != current); rwsem_clear_owner(sem); if (unlikely(atomic_long_sub_return_release(RWSEM_ACTIVE_WRITE_BIAS, &sem->count) < 0)) @@ -277,6 +284,7 @@ static inline void __downgrade_write(struct rw_semaphore *sem) * read-locked region is ok to be re-ordered into the * write side. As such, rely on RELEASE semantics. */ + DEBUG_RWSEMS_WARN_ON(sem->owner != current); tmp = atomic_long_add_return_release(-RWSEM_WAITING_BIAS, &sem->count); rwsem_set_reader_owned(sem); if (tmp < 0) |