fix sem_close unmapping of still-referenced semaphore

[musl] / src / thread / __timedwait.c

diff --git a/src/thread/__timedwait.c b/src/thread/__timedwait.c
index ae19bd6..666093b 100644 (file)
--- a/src/thread/__timedwait.c
+++ b/src/thread/__timedwait.c
@@ -5,6 +5,27 @@
 #include "syscall.h"
 #include "pthread_impl.h"
 
+#define IS32BIT(x) !((x)+0x80000000ULL>>32)
+#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63))
+
+static int __futex4_cp(volatile void *addr, int op, int val, const struct timespec *to)
+{
+       int r;
+#ifdef SYS_futex_time64
+       time_t s = to ? to->tv_sec : 0;
+       long ns = to ? to->tv_nsec : 0;
+       r = -ENOSYS;
+       if (SYS_futex == SYS_futex_time64 || !IS32BIT(s))
+               r = __syscall_cp(SYS_futex_time64, addr, op, val,
+                       to ? ((long long[]){s, ns}) : 0);
+       if (SYS_futex == SYS_futex_time64 || r!=-ENOSYS) return r;
+       to = to ? (void *)(long[]){CLAMP(s), ns} : 0;
+#endif
+       r = __syscall_cp(SYS_futex, addr, op, val, to);
+       if (r != -ENOSYS) return r;
+       return __syscall_cp(SYS_futex, addr, op & ~FUTEX_PRIVATE, val, to);
+}
+
 static volatile int dummy = 0;
 weak_alias(dummy, __eintr_valid_flag);
 
@@ -28,8 +49,7 @@ int __timedwait_cp(volatile int *addr, int val,
                top = &to;
        }
 
-       r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT|priv, val, top);
-       if (r == ENOSYS) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top);
+       r = -__futex4_cp(addr, FUTEX_WAIT|priv, val, top);
        if (r != EINTR && r != ETIMEDOUT && r != ECANCELED) r = 0;
        /* Mitigate bug in old kernels wrongly reporting EINTR for non-
         * interrupting (SA_RESTART) signal handlers. This is only practical