Change atfork lock from mutex to rwlock, also make mutexes used by malloc()
module private type, when private type mutex is locked/unlocked, thread critical region is entered or leaved. These changes makes fork() async-signal safe which required by POSIX. Note that user's atfork handler still needs to be async-signal safe, but it is not problem of libthr, it is user's responsiblity.
This commit is contained in:
parent
02c3c85869
commit
ada33a6e36
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=212077
@ -89,9 +89,9 @@ _pthread_atfork(void (*prepare)(void), void (*parent)(void),
|
||||
af->prepare = prepare;
|
||||
af->parent = parent;
|
||||
af->child = child;
|
||||
THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock);
|
||||
_thr_rwl_rdlock(&_thr_atfork_lock);
|
||||
TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe);
|
||||
THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock);
|
||||
_thr_rwl_unlock(&_thr_atfork_lock);
|
||||
return (0);
|
||||
}
|
||||
|
||||
@ -104,7 +104,7 @@ __pthread_cxa_finalize(struct dl_phdr_info *phdr_info)
|
||||
_thr_check_init();
|
||||
|
||||
curthread = _get_curthread();
|
||||
THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock);
|
||||
_thr_rwl_wrlock(&_thr_atfork_lock);
|
||||
TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) {
|
||||
if (__elf_phdr_match_addr(phdr_info, af->prepare) ||
|
||||
__elf_phdr_match_addr(phdr_info, af->parent) ||
|
||||
@ -113,7 +113,7 @@ __pthread_cxa_finalize(struct dl_phdr_info *phdr_info)
|
||||
free(af);
|
||||
}
|
||||
}
|
||||
THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock);
|
||||
_thr_rwl_unlock(&_thr_atfork_lock);
|
||||
_thr_tsd_unload(phdr_info);
|
||||
_thr_sigact_unload(phdr_info);
|
||||
}
|
||||
@ -137,7 +137,7 @@ _fork(void)
|
||||
|
||||
curthread = _get_curthread();
|
||||
|
||||
THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock);
|
||||
_thr_rwl_rdlock(&_thr_atfork_lock);
|
||||
|
||||
/* Run down atfork prepare handlers. */
|
||||
TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) {
|
||||
@ -145,6 +145,12 @@ _fork(void)
|
||||
af->prepare();
|
||||
}
|
||||
|
||||
/*
|
||||
* Block all signals until we reach a safe point.
|
||||
*/
|
||||
_thr_signal_block(curthread);
|
||||
_thr_signal_prefork();
|
||||
|
||||
/*
|
||||
* All bets are off as to what should happen soon if the parent
|
||||
* process was not so kindly as to set up pthread fork hooks to
|
||||
@ -158,12 +164,6 @@ _fork(void)
|
||||
was_threaded = 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Block all signals until we reach a safe point.
|
||||
*/
|
||||
_thr_signal_block(curthread);
|
||||
_thr_signal_prefork();
|
||||
|
||||
/* Fork a new process: */
|
||||
if ((ret = __sys_fork()) == 0) {
|
||||
/* Child process */
|
||||
@ -182,7 +182,7 @@ _fork(void)
|
||||
|
||||
/* clear other threads locked us. */
|
||||
_thr_umutex_init(&curthread->lock);
|
||||
_thr_umutex_init(&_thr_atfork_lock);
|
||||
_mutex_fork(curthread);
|
||||
|
||||
_thr_signal_postfork_child();
|
||||
|
||||
@ -192,13 +192,12 @@ _fork(void)
|
||||
|
||||
/* reinitialize libc spinlocks. */
|
||||
_thr_spinlock_init();
|
||||
_mutex_fork(curthread);
|
||||
|
||||
/* reinitalize library. */
|
||||
_libpthread_init(curthread);
|
||||
|
||||
/* Ready to continue, unblock signals. */
|
||||
_thr_signal_unblock(curthread);
|
||||
/* atfork is reinitializeded by _libpthread_init()! */
|
||||
_thr_rwl_rdlock(&_thr_atfork_lock);
|
||||
|
||||
if (was_threaded) {
|
||||
__isthreaded = 1;
|
||||
@ -206,32 +205,36 @@ _fork(void)
|
||||
__isthreaded = 0;
|
||||
}
|
||||
|
||||
/* Ready to continue, unblock signals. */
|
||||
_thr_signal_unblock(curthread);
|
||||
|
||||
/* Run down atfork child handlers. */
|
||||
TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
|
||||
if (af->child != NULL)
|
||||
af->child();
|
||||
}
|
||||
_thr_rwlock_unlock(&_thr_atfork_lock);
|
||||
} else {
|
||||
/* Parent process */
|
||||
errsave = errno;
|
||||
|
||||
_thr_signal_postfork();
|
||||
|
||||
/* Ready to continue, unblock signals. */
|
||||
_thr_signal_unblock(curthread);
|
||||
|
||||
if (was_threaded) {
|
||||
_rtld_atfork_post(rtld_locks);
|
||||
_malloc_postfork();
|
||||
}
|
||||
|
||||
/* Ready to continue, unblock signals. */
|
||||
_thr_signal_unblock(curthread);
|
||||
|
||||
/* Run down atfork parent handlers. */
|
||||
TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
|
||||
if (af->parent != NULL)
|
||||
af->parent();
|
||||
}
|
||||
|
||||
THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock);
|
||||
_thr_rwlock_unlock(&_thr_atfork_lock);
|
||||
}
|
||||
errno = errsave;
|
||||
|
||||
|
@ -65,7 +65,7 @@ pthreadlist _thread_list = TAILQ_HEAD_INITIALIZER(_thread_list);
|
||||
pthreadlist _thread_gc_list = TAILQ_HEAD_INITIALIZER(_thread_gc_list);
|
||||
int _thread_active_threads = 1;
|
||||
atfork_head _thr_atfork_list = TAILQ_HEAD_INITIALIZER(_thr_atfork_list);
|
||||
struct umutex _thr_atfork_lock = DEFAULT_UMUTEX;
|
||||
struct urwlock _thr_atfork_lock = DEFAULT_URWLOCK;
|
||||
|
||||
struct pthread_prio _thr_priorities[3] = {
|
||||
{RTP_PRIO_MIN, RTP_PRIO_MAX, 0}, /* FIFO */
|
||||
@ -427,7 +427,7 @@ init_private(void)
|
||||
_thr_umutex_init(&_cond_static_lock);
|
||||
_thr_umutex_init(&_rwlock_static_lock);
|
||||
_thr_umutex_init(&_keytable_lock);
|
||||
_thr_umutex_init(&_thr_atfork_lock);
|
||||
_thr_urwlock_init(&_thr_atfork_lock);
|
||||
_thr_umutex_init(&_thr_event_lock);
|
||||
_thr_once_init();
|
||||
_thr_spinlock_init();
|
||||
|
@ -224,8 +224,12 @@ _pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
|
||||
.m_ceiling = 0
|
||||
};
|
||||
static const struct pthread_mutex_attr *pattr = &attr;
|
||||
int ret;
|
||||
|
||||
return mutex_init(mutex, (pthread_mutexattr_t *)&pattr, calloc_cb);
|
||||
ret = mutex_init(mutex, (pthread_mutexattr_t *)&pattr, calloc_cb);
|
||||
if (ret == 0)
|
||||
(*mutex)->m_private = 1;
|
||||
return (ret);
|
||||
}
|
||||
|
||||
void
|
||||
@ -319,13 +323,16 @@ mutex_trylock_common(struct pthread *curthread, pthread_mutex_t *mutex)
|
||||
|
||||
id = TID(curthread);
|
||||
m = *mutex;
|
||||
if (m->m_private)
|
||||
THR_CRITICAL_ENTER(curthread);
|
||||
ret = _thr_umutex_trylock(&m->m_lock, id);
|
||||
if (ret == 0) {
|
||||
ENQUEUE_MUTEX(curthread, m);
|
||||
} else if (m->m_owner == curthread) {
|
||||
ret = mutex_self_trylock(m);
|
||||
} /* else {} */
|
||||
|
||||
if (ret && m->m_private)
|
||||
THR_CRITICAL_LEAVE(curthread);
|
||||
return (ret);
|
||||
}
|
||||
|
||||
@ -417,13 +424,19 @@ static inline int
|
||||
mutex_lock_common(struct pthread *curthread, struct pthread_mutex *m,
|
||||
const struct timespec *abstime)
|
||||
{
|
||||
int ret;
|
||||
|
||||
if (m->m_private)
|
||||
THR_CRITICAL_ENTER(curthread);
|
||||
if (_thr_umutex_trylock2(&m->m_lock, TID(curthread)) == 0) {
|
||||
ENQUEUE_MUTEX(curthread, m);
|
||||
return (0);
|
||||
ret = 0;
|
||||
} else {
|
||||
ret = mutex_lock_sleep(curthread, m, abstime);
|
||||
}
|
||||
|
||||
return (mutex_lock_sleep(curthread, m, abstime));
|
||||
if (ret && m->m_private)
|
||||
THR_CRITICAL_LEAVE(curthread);
|
||||
return (ret);
|
||||
}
|
||||
|
||||
int
|
||||
@ -625,6 +638,8 @@ mutex_unlock_common(pthread_mutex_t *mutex)
|
||||
MUTEX_INIT_LINK(m);
|
||||
_thr_umutex_unlock(&m->m_lock, id);
|
||||
}
|
||||
if (m->m_private)
|
||||
THR_CRITICAL_LEAVE(curthread);
|
||||
return (0);
|
||||
}
|
||||
|
||||
@ -660,6 +675,9 @@ _mutex_cv_unlock(pthread_mutex_t *mutex, int *count)
|
||||
}
|
||||
MUTEX_INIT_LINK(m);
|
||||
_thr_umutex_unlock(&m->m_lock, TID(curthread));
|
||||
|
||||
if (m->m_private)
|
||||
THR_CRITICAL_LEAVE(curthread);
|
||||
return (0);
|
||||
}
|
||||
|
||||
|
@ -132,6 +132,7 @@ struct pthread_mutex {
|
||||
int m_refcount;
|
||||
int m_spinloops;
|
||||
int m_yieldloops;
|
||||
int m_private;
|
||||
/*
|
||||
* Link for all mutexes a thread currently owns.
|
||||
*/
|
||||
@ -587,7 +588,7 @@ extern pthreadlist _thread_gc_list __hidden;
|
||||
|
||||
extern int _thread_active_threads;
|
||||
extern atfork_head _thr_atfork_list __hidden;
|
||||
extern struct umutex _thr_atfork_lock __hidden;
|
||||
extern struct urwlock _thr_atfork_lock __hidden;
|
||||
|
||||
/* Default thread attributes: */
|
||||
extern struct pthread_attr _pthread_attr_default __hidden;
|
||||
|
@ -47,6 +47,13 @@ _thr_umutex_init(struct umutex *mtx)
|
||||
*mtx = default_mtx;
|
||||
}
|
||||
|
||||
void
|
||||
_thr_urwlock_init(struct urwlock *rwl)
|
||||
{
|
||||
static struct urwlock default_rwl = DEFAULT_URWLOCK;
|
||||
*rwl = default_rwl;
|
||||
}
|
||||
|
||||
int
|
||||
__thr_umutex_lock(struct umutex *mtx, uint32_t id)
|
||||
{
|
||||
|
@ -32,7 +32,8 @@
|
||||
#include <strings.h>
|
||||
#include <sys/umtx.h>
|
||||
|
||||
#define DEFAULT_UMUTEX {0,0, {0,0},{0,0,0,0}}
|
||||
#define DEFAULT_UMUTEX {0,0,{0,0},{0,0,0,0}}
|
||||
#define DEFAULT_URWLOCK {0,0,0,0,{0,0,0,0}}
|
||||
|
||||
int __thr_umutex_lock(struct umutex *mtx, uint32_t id) __hidden;
|
||||
int __thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
|
||||
@ -43,6 +44,8 @@ int __thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
|
||||
uint32_t *oldceiling) __hidden;
|
||||
|
||||
void _thr_umutex_init(struct umutex *mtx) __hidden;
|
||||
void _thr_urwlock_init(struct urwlock *rwl) __hidden;
|
||||
|
||||
int _thr_umtx_wait(volatile long *mtx, long exp,
|
||||
const struct timespec *timeout) __hidden;
|
||||
int _thr_umtx_wait_uint(volatile u_int *mtx, u_int exp,
|
||||
|
Loading…
Reference in New Issue
Block a user