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locking/rwsem: Check for operations on an uninitialized rwsem

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Currently rwsems is the only locking primitive that lacks this
debug feature. Add it under CONFIG_DEBUG_RWSEMS and do the magic
checking in the locking fastpath (trylock) operation such that
we cover all cases. The unlocking part is pretty straightforward.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: mingo@kernel.org
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: https://lkml.kernel.org/r/20190729044735.9632-1-dave@stgolabs.net
This commit is contained in:
Davidlohr Bueso
2019-07-28 21:47:35 -07:00
committed by Peter Zijlstra
parent 91d2a812df
commit fce45cd411
2 changed files with 28 additions and 4 deletions
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10
include/linux/rwsem.h
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@@ -45,6 +45,9 @@ struct rw_semaphore {
#endif
raw_spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_RWSEMS
void *magic;
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
@@ -73,6 +76,12 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
# define __RWSEM_DEP_MAP_INIT(lockname)
#endif
#ifdef CONFIG_DEBUG_RWSEMS
# define __DEBUG_RWSEM_INITIALIZER(lockname) , .magic = &lockname
#else
# define __DEBUG_RWSEM_INITIALIZER(lockname)
#endif
#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED
#else
@@ -85,6 +94,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
.wait_list = LIST_HEAD_INIT((name).wait_list), \
.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock) \
__RWSEM_OPT_INIT(name) \
__DEBUG_RWSEM_INITIALIZER(name) \
__RWSEM_DEP_MAP_INIT(name) }
#define DECLARE_RWSEM(name) \