//src and dest are user controlled but must be valid.
TrustedPart_for_safe_jit(mutext, uint8_t *src,uint8_t *dest, uint32_t size) // in the current case, *dest targets a PROT_NONE memory region
{
    MutexLock(mutext);
    ValidateOpcodes(src,size); // uses calls to mmap on size internally. Contains many loops : this is the longest part.
    unwriteprotect(dest,size); // calls many sandbox’s internal functions

    SafeMemcpy(src,dest,size); // THIS IS the function which contains the race condition

    asm("mfence");
    unEXECprotect(dest,size); // involve write protecting as well as allowing reading
    MutexUnlock(mutext);
}

SafeMemcpy(uint8_t *src,uint8_t *dest, uint32_t size) // the data to be copied cannot exceed 128Mb
{
    if(!CheckUserTarget(dest,size) {
        uint8_t *src_ptr=src;
        uint8_t *dest_ptr=dest;
        uint8_t *end_ptr=des+size;
        while (dest_ptr < end_ptr) { // that loop should execute very fast
            *(uint32_t *) dest_ptr = *(uint32_t *) src_ptr;
            dest_ptr += 32;
            src_ptr += 32;
        }
    }
}