Loading
powerpc: use clear_tasks_mm_cpumask()
Current CPU hotplug code has some task->mm handling issues: 1. Working with task->mm w/o getting mm or grabing the task lock is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). We can't use get_task_mm()/mmput() pair as mmput() might sleep, so we must take the task lock while handle its mm. 2. Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To fix this we would need to use find_lock_task_mm(), which would walk up all threads and returns an appropriate task (with task lock held). clear_tasks_mm_cpumask() has all the issues fixed, so let's use it. Suggested-by:Oleg Nesterov <oleg@redhat.com> Signed-off-by: