On 05/27, Minchan Kim wrote: > > > another problem is that pid_task(pid) can return a zombie leader, in this case > > mm_access() will fail while it shouldn't. > > I'm sorry. I didn't notice that. However, I couldn't understand your point. > Why do you think mm_access shouldn't fail even though pid_task returns > a zombie leader? The leader can exit (call sys_exit(), not sys_exit_group()), this won't affect other threads. In this case the process is still alive even if the leader thread is zombie. That is why we have find_lock_task_mm(). Oleg.
