#ifndef LOCKING_H #define LOCKING_H #include struct spinlock { pthread_spinlock_t lock; }; struct mutexlock { pthread_mutex_t lock; }; #define MUTEXLOCK_INITIALIZER { .lock = PTHREAD_MUTEX_INITIALIZER } struct rwlock { pthread_rwlock_t lock; }; struct condlock { pthread_mutex_t lock; pthread_cond_t cond; }; static inline int spinlock_init(struct spinlock *l) { return -pthread_spin_init(&l->lock, 0); } static inline void spinlock_destroy(struct spinlock *l) { pthread_spin_destroy(&l->lock); } static inline void spinlock_lock(struct spinlock *l) { pthread_spin_lock(&l->lock); } static inline void spinlock_unlock(struct spinlock *l) { pthread_spin_unlock(&l->lock); } static inline int mutexlock_init(struct mutexlock *l) { return -pthread_mutex_init(&l->lock, 0); } static inline void mutexlock_destroy(struct mutexlock *l) { pthread_mutex_destroy(&l->lock); } static inline void mutexlock_lock(struct mutexlock *l) { pthread_mutex_lock(&l->lock); } static inline void mutexlock_unlock(struct mutexlock *l) { pthread_mutex_unlock(&l->lock); } static inline int rwlock_init(struct rwlock *l) { return -pthread_rwlock_init(&l->lock, 0); } static inline int rwlock_init2(struct rwlock *l, pthread_rwlockattr_t *attr) { return -pthread_rwlock_init(&l->lock, attr); } static inline void rwlock_destroy(struct rwlock *l) { pthread_rwlock_destroy(&l->lock); } static inline void rwlock_rd_lock(struct rwlock *l) { pthread_rwlock_rdlock(&l->lock); } static inline void rwlock_wr_lock(struct rwlock *l) { pthread_rwlock_wrlock(&l->lock); } static inline void rwlock_unlock(struct rwlock *l) { pthread_rwlock_unlock(&l->lock); } static inline void condlock_init(struct condlock *c) { pthread_mutex_init(&c->lock, NULL); pthread_cond_init(&c->cond, NULL); } static inline void condlock_signal(struct condlock *c) { pthread_mutex_lock(&c->lock); pthread_cond_signal(&c->cond); pthread_mutex_unlock(&c->lock); } static inline void condlock_wait(struct condlock *c) { pthread_mutex_lock(&c->lock); pthread_cond_wait(&c->cond, &c->lock); pthread_mutex_unlock(&c->lock); } static inline void condlock_destroy(struct condlock *c) { pthread_mutex_destroy(&c->lock); pthread_cond_destroy(&c->cond); } #endif /* LOCKING_H */ g/net/bluetooth/hci_request.h'>
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authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /net/bluetooth/hci_request.h
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'net/bluetooth/hci_request.h')