This does not correspond to any NT syscall, but rather should be called by the user-space NT emulator when a thread dies. It is responsible for marking any mutexes owned by that thread as abandoned.
Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- drivers/misc/ntsync.c | 80 ++++++++++++++++++++++++++++++++++++- include/uapi/linux/ntsync.h | 1 + 2 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 28f43768d1c3..1173c750c106 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -64,6 +64,7 @@ struct ntsync_obj { struct { __u32 count; __u32 owner; + bool ownerdead; } mutex; } u; }; @@ -87,6 +88,7 @@ struct ntsync_q { atomic_t signaled;
bool all; + bool ownerdead; __u32 count; struct ntsync_q_entry entries[]; }; @@ -240,6 +242,9 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q, obj->u.sem.count--; break; case NTSYNC_TYPE_MUTEX: + if (obj->u.mutex.ownerdead) + q->ownerdead = true; + obj->u.mutex.ownerdead = false; obj->u.mutex.count++; obj->u.mutex.owner = q->owner; break; @@ -299,6 +304,9 @@ static void try_wake_any_mutex(struct ntsync_obj *mutex) continue;
if (atomic_cmpxchg(&q->signaled, -1, entry->index) == -1) { + if (mutex->u.mutex.ownerdead) + q->ownerdead = true; + mutex->u.mutex.ownerdead = false; mutex->u.mutex.count++; mutex->u.mutex.owner = q->owner; wake_up_process(q->task); @@ -514,6 +522,71 @@ static int ntsync_put_mutex(struct ntsync_device *dev, void __user *argp) return ret; }
+/* + * Actually change the mutex state to mark its owner as dead. + */ +static void put_mutex_ownerdead_state(struct ntsync_obj *mutex) +{ + lockdep_assert_held(&mutex->lock); + + mutex->u.mutex.ownerdead = true; + mutex->u.mutex.owner = 0; + mutex->u.mutex.count = 0; +} + +static int ntsync_kill_owner(struct ntsync_device *dev, void __user *argp) +{ + struct ntsync_obj *obj; + unsigned long id; + __u32 owner; + + if (get_user(owner, (__u32 __user *)argp)) + return -EFAULT; + if (!owner) + return -EINVAL; + + rcu_read_lock(); + + xa_for_each(&dev->objects, id, obj) { + if (!kref_get_unless_zero(&obj->refcount)) + continue; + + if (obj->type != NTSYNC_TYPE_MUTEX) { + put_obj(obj); + continue; + } + + if (atomic_read(&obj->all_hint) > 0) { + spin_lock(&dev->wait_all_lock); + spin_lock_nest_lock(&obj->lock, &dev->wait_all_lock); + + if (obj->u.mutex.owner == owner) { + put_mutex_ownerdead_state(obj); + try_wake_all_obj(dev, obj); + try_wake_any_mutex(obj); + } + + spin_unlock(&obj->lock); + spin_unlock(&dev->wait_all_lock); + } else { + spin_lock(&obj->lock); + + if (obj->u.mutex.owner == owner) { + put_mutex_ownerdead_state(obj); + try_wake_any_mutex(obj); + } + + spin_unlock(&obj->lock); + } + + put_obj(obj); + } + + rcu_read_unlock(); + + return 0; +} + static int ntsync_schedule(const struct ntsync_q *q, ktime_t *timeout) { int ret = 0; @@ -585,6 +658,7 @@ static int setup_wait(struct ntsync_device *dev, q->owner = args->owner; atomic_set(&q->signaled, -1); q->all = all; + q->ownerdead = false; q->count = count;
for (i = 0; i < count; i++) { @@ -697,7 +771,7 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp) struct ntsync_wait_args __user *user_args = argp;
/* even if we caught a signal, we need to communicate success */ - ret = 0; + ret = q->ownerdead ? -EOWNERDEAD : 0;
if (put_user(signaled, &user_args->index)) ret = -EFAULT; @@ -778,7 +852,7 @@ static int ntsync_wait_all(struct ntsync_device *dev, void __user *argp) struct ntsync_wait_args __user *user_args = argp;
/* even if we caught a signal, we need to communicate success */ - ret = 0; + ret = q->ownerdead ? -EOWNERDEAD : 0;
if (put_user(signaled, &user_args->index)) ret = -EFAULT; @@ -803,6 +877,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd, return ntsync_create_sem(dev, argp); case NTSYNC_IOC_DELETE: return ntsync_delete(dev, argp); + case NTSYNC_IOC_KILL_OWNER: + return ntsync_kill_owner(dev, argp); case NTSYNC_IOC_PUT_MUTEX: return ntsync_put_mutex(dev, argp); case NTSYNC_IOC_PUT_SEM: diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 2e44e7e77776..fec9a3993322 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -48,5 +48,6 @@ struct ntsync_wait_args { struct ntsync_mutex_args) #define NTSYNC_IOC_PUT_MUTEX _IOWR(NTSYNC_IOC_BASE, 6, \ struct ntsync_mutex_args) +#define NTSYNC_IOC_KILL_OWNER _IOW (NTSYNC_IOC_BASE, 7, __u32)
#endif