fix integer overflow in WIFSTOPPED macro

[musl] / src / stdio / __lockfile.c

diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c
index 2ff75d8..0f60a14 100644 (file)
--- a/src/stdio/__lockfile.c
+++ b/src/stdio/__lockfile.c
@@ -1,20 +1,18 @@
 #include "stdio_impl.h"
 #include "pthread_impl.h"
 
-#define MAYBE_WAITERS 0x40000000
-
 int __lockfile(FILE *f)
 {
        int owner = f->lock, tid = __pthread_self()->tid;
        if ((owner & ~MAYBE_WAITERS) == tid)
                return 0;
-       for (;;) {
-               owner = a_cas(&f->lock, 0, tid);
-               if (!owner) return 1;
-               if (a_cas(&f->lock, owner, owner|MAYBE_WAITERS)==owner) break;
+       owner = a_cas(&f->lock, 0, tid);
+       if (!owner) return 1;
+       while ((owner = a_cas(&f->lock, 0, tid|MAYBE_WAITERS))) {
+               if ((owner & MAYBE_WAITERS) ||
+                   a_cas(&f->lock, owner, owner|MAYBE_WAITERS)==owner)
+                       __futexwait(&f->lock, owner|MAYBE_WAITERS, 1);
        }
-       while ((owner = a_cas(&f->lock, 0, tid|MAYBE_WAITERS)))
-               __futexwait(&f->lock, owner, 1);
        return 1;
 }