For spin-locks that are initialized dynamically, the initial value of the lock word needs to be propagated to the other processors, before they can attempt to lock this lock.
The function MemoryBarrier() is part of the Windows API. <https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-memorybarrier> 2020-07-01 Bruno Haible <br...@clisp.org> windows-spin: Fix race condition on multiprocessor systems. * lib/windows-spin.c (glwthread_spin_init): Add a memory barrier. diff --git a/lib/windows-spin.c b/lib/windows-spin.c index b90e7ae..4643ac1 100644 --- a/lib/windows-spin.c +++ b/lib/windows-spin.c @@ -27,6 +27,7 @@ void glwthread_spin_init (glwthread_spinlock_t *lock) { lock->word = 0; + MemoryBarrier (); } int
