fix pthread_detach inadvertently acting as cancellation point in race case

[musl] / src / thread / pthread_barrier_wait.c

diff --git a/src/thread/pthread_barrier_wait.c b/src/thread/pthread_barrier_wait.c
index 4a964fe..cc2a8bb 100644 (file)
--- a/src/thread/pthread_barrier_wait.c
+++ b/src/thread/pthread_barrier_wait.c
@@ -1,8 +1,5 @@
 #include "pthread_impl.h"
 
-void __vm_lock_impl(int);
-void __vm_unlock_impl(void);
-
 static int pshared_barrier_wait(pthread_barrier_t *b)
 {
        int limit = (b->_b_limit & INT_MAX) + 1;
@@ -26,7 +23,7 @@ static int pshared_barrier_wait(pthread_barrier_t *b)
                        __wait(&b->_b_count, &b->_b_waiters2, v, 0);
        }
 
-       __vm_lock_impl(+1);
+       __vm_lock();
 
        /* Ensure all threads have a vm lock before proceeding */
        if (a_fetch_add(&b->_b_count, -1)==1-limit) {
@@ -47,17 +44,17 @@ static int pshared_barrier_wait(pthread_barrier_t *b)
        if (v==INT_MIN+1 || (v==1 && w))
                __wake(&b->_b_lock, 1, 0);
 
-       __vm_unlock_impl();
+       __vm_unlock();
 
        return ret;
 }
 
 struct instance
 {
-       int count;
-       int last;
-       int waiters;
-       int finished;
+       volatile int count;
+       volatile int last;
+       volatile int waiters;
+       volatile int finished;
 };
 
 int pthread_barrier_wait(pthread_barrier_t *b)
@@ -79,7 +76,7 @@ int pthread_barrier_wait(pthread_barrier_t *b)
        /* First thread to enter the barrier becomes the "instance owner" */
        if (!inst) {
                struct instance new_inst = { 0 };
-               int spins = 10000;
+               int spins = 200;
                b->_b_inst = inst = &new_inst;
                a_store(&b->_b_lock, 0);
                if (b->_b_waiters) __wake(&b->_b_lock, 1, 1);
@@ -87,7 +84,7 @@ int pthread_barrier_wait(pthread_barrier_t *b)
                        a_spin();
                a_inc(&inst->finished);
                while (inst->finished == 1)
-                       __syscall(SYS_futex,&inst->finished,FUTEX_WAIT|128,1,0) != -ENOSYS
+                       __syscall(SYS_futex,&inst->finished,FUTEX_WAIT|FUTEX_PRIVATE,1,0) != -ENOSYS
                        || __syscall(SYS_futex,&inst->finished,FUTEX_WAIT,1,0);
                return PTHREAD_BARRIER_SERIAL_THREAD;
        }