> Inside exec.c, there is a race:
>
> -------
> static bool prepare_mmio_access(MemoryRegion *mr)
> {
> bool unlocked = !qemu_mutex_iothread_locked();
> bool release_lock = false;
>
> if (unlocked && mr->global_locking) {
> qemu_mutex_lock_iothread();
> ------
>
> IMHO, checking for unlocked that way is wrong. Should use some kind
> of _trylock instead?
Answering this myself: above code is correct, because "iothread_locked" is a
thread local var,
and we want to lock the mutex if we did not already...
