Initialize the mutex before making us of it from many threads. Prevents

a race in which one thread is currently initializing the mutex which is
not an atomic operation whereas another thread tries to use it too
early.

With and ok schwarze@

diff --git a/regress/lib/libc/locale/uselocale/uselocale.c b/regress/lib/libc/locale/uselocale/uselocale.c
index 445bb64..f07a16a 100644 (file)
--- a/regress/lib/libc/locale/uselocale/uselocale.c
+++ b/regress/lib/libc/locale/uselocale/uselocale.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: uselocale.c,v 1.5 2017/08/16 13:52:50 schwarze Exp $ */
+/* $OpenBSD: uselocale.c,v 1.6 2022/04/03 16:52:50 anton Exp $ */
 /*
  * Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
  *
@@ -170,6 +170,10 @@ _test_MB_CUR_MAX(int line, int ee, size_t ar)
 #define        TEST_R(Fn, ...)         _test_##Fn(__LINE__, 0, __VA_ARGS__)
 #define        TEST_ER(Fn, ...)        _test_##Fn(__LINE__, __VA_ARGS__)
 
+static pthread_mutex_t          mtx;
+static pthread_mutexattr_t      mtxattr;
+static pthread_cond_t           cond;
+
 /*
  * SWITCH_SIGNAL wakes the other thread.
  * SWITCH_WAIT goes to sleep.
@@ -179,40 +183,21 @@ _test_MB_CUR_MAX(int line, int ee, size_t ar)
 static void
 switch_thread(int step, int flags)
 {
-       static pthread_mutexattr_t       ma;
-       static struct timespec           t;
-       static pthread_cond_t           *c;
-       static pthread_mutex_t          *m;
-       int                              irc;
-
-       if (m == NULL) {
-               if ((m = malloc(sizeof(*m))) == NULL)
-                       err(1, NULL);
-               if ((irc = pthread_mutexattr_init(&ma)) != 0)
-                       errc(1, irc, "pthread_mutexattr_init");
-               if ((irc = pthread_mutexattr_settype(&ma,
-                   PTHREAD_MUTEX_STRICT_NP)) != 0)
-                       errc(1, irc, "pthread_mutexattr_settype");
-               if ((irc = pthread_mutex_init(m, &ma)) != 0)
-                       errc(1, irc, "pthread_mutex_init");
-       }
-       if (c == NULL) {
-               if ((c = malloc(sizeof(*c))) == NULL)
-                       err(1, NULL);
-               if ((irc = pthread_cond_init(c, NULL)) != 0)
-                       errc(1, irc, "pthread_cond_init");
-       }
+       struct timespec  t;
+       int              irc;
+
        if (flags & SWITCH_SIGNAL) {
-               if ((irc = pthread_cond_signal(c)) != 0)
+               if ((irc = pthread_cond_signal(&cond)) != 0)
                        errc(1, irc, "pthread_cond_signal(%d)", step);
        }
        if (flags & SWITCH_WAIT) {
-               if ((irc = pthread_mutex_trylock(m)) != 0)
+               if ((irc = pthread_mutex_trylock(&mtx)) != 0)
                        errc(1, irc, "pthread_mutex_trylock(%d)", step);
                t.tv_sec = time(NULL) + 2;
-               if ((irc = pthread_cond_timedwait(c, m, &t)) != 0)
+               t.tv_nsec = 0;
+               if ((irc = pthread_cond_timedwait(&cond, &mtx, &t)) != 0)
                        errc(1, irc, "pthread_cond_timedwait(%d)", step);
-               if ((irc = pthread_mutex_unlock(m)) != 0)
+               if ((irc = pthread_mutex_unlock(&mtx)) != 0)
                        errc(1, irc, "pthread_mutex_unlock(%d)", step);
        }
 }
@@ -442,6 +427,16 @@ main(void)
        unsetenv("LC_MESSAGES");
        unsetenv("LANG");
 
+       if ((irc = pthread_mutexattr_init(&mtxattr)) != 0)
+               errc(1, irc, "pthread_mutexattr_init");
+       if ((irc = pthread_mutexattr_settype(&mtxattr,
+           PTHREAD_MUTEX_STRICT_NP)) != 0)
+               errc(1, irc, "pthread_mutexattr_settype");
+       if ((irc = pthread_mutex_init(&mtx, &mtxattr)) != 0)
+               errc(1, irc, "pthread_mutex_init");
+       if ((irc = pthread_cond_init(&cond, NULL)) != 0)
+               errc(1, irc, "pthread_cond_init");
+
        /* First let the child do some tests. */
        if ((irc = pthread_create(&child_thread, NULL, child_func, NULL)) != 0)
                errc(1, irc, "pthread_create");