tree 383b30bc13af8ce83e15825b041d8bb791ea4cea
parent 17406b82d621930cca8ccc1272cdac9a7dae8e40
author Frederic Weisbecker <fweisbec@gmail.com> 1234281157 +0100
committer Ingo Molnar <mingo@elte.hu> 1234346656 +0100

softlockup: ensure the task has been switched out once

When we check if a task has been switched out since the last scan, we might
have a race condition on the following scenario:

- the task is freshly created and scheduled

- it puts its state to TASK_UNINTERRUPTIBLE and is not yet switched out

- check_hung_task() scans this task and will report a false positive because
  t->nvcsw + t->nivcsw == t->last_switch_count == 0

Add a check for such cases.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>