Hi： See lock_hash in h_table.c: Flowing lines of code do not guarantee atomicity and I think it is not safe: -      atomic_get(&_tm_table->entries[i].locker_pid) != mypid -      lock(&_tm_table->entries[i].mutex) -      atomic_set(&_tm_table->entries[i].locker_pid, mypid) Would you mind solving my confusion?