diff options
Diffstat (limited to 'src/thread/pthread_create.c')
| -rw-r--r-- | src/thread/pthread_create.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index a86b5e1b..e07d29e3 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -37,8 +37,6 @@ _Noreturn void __pthread_exit(void *result) __pthread_tsd_run_dtors(); - LOCK(self->exitlock); - /* Access to target the exiting thread with syscalls that use * its kernel tid is controlled by killlock. For detached threads, * any use past this point would have undefined behavior, but for @@ -85,15 +83,19 @@ _Noreturn void __pthread_exit(void *result) __do_orphaned_stdio_locks(); __dl_thread_cleanup(); - if (self->detached && self->map_base) { + /* This atomic potentially competes with a concurrent pthread_detach + * call; the loser is responsible for freeing thread resources. */ + int state = a_cas(&self->detach_state, DT_JOINABLE, DT_EXITING); + + if (state>=DT_DETACHED && self->map_base) { /* Detached threads must avoid the kernel clear_child_tid * feature, since the virtual address will have been * unmapped and possibly already reused by a new mapping * at the time the kernel would perform the write. In * the case of threads that started out detached, the * initial clone flags are correct, but if the thread was - * detached later (== 2), we need to clear it here. */ - if (self->detached == 2) __syscall(SYS_set_tid_address, 0); + * detached later, we need to clear it here. */ + if (state == DT_DYNAMIC) __syscall(SYS_set_tid_address, 0); /* Robust list will no longer be valid, and was already * processed above, so unregister it with the kernel. */ @@ -141,7 +143,7 @@ static int start(void *p) if (self->startlock[0]) { __wait(self->startlock, 0, 1, 1); if (self->startlock[0] == 2) { - self->detached = 2; + self->detach_state = DT_DYNAMIC; pthread_exit(0); } __restore_sigs(self->sigmask); @@ -274,8 +276,10 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att new->tsd = (void *)tsd; new->locale = &libc.global_locale; if (attr._a_detach) { - new->detached = 1; + new->detach_state = DT_DETACHED; flags -= CLONE_CHILD_CLEARTID; + } else { + new->detach_state = DT_JOINABLE; } if (attr._a_sched) { do_sched = new->startlock[0] = 1; @@ -284,10 +288,9 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att new->robust_list.head = &new->robust_list.head; new->unblock_cancel = self->cancel; new->CANARY = self->CANARY; - new->join_futex = -1; a_inc(&libc.threads_minus_1); - ret = __clone((c11 ? start_c11 : start), stack, flags, new, &new->tid, TP_ADJ(new), &new->join_futex); + ret = __clone((c11 ? start_c11 : start), stack, flags, new, &new->tid, TP_ADJ(new), &new->detach_state); __release_ptc(); |