Commit d49f47f8 authored May 10, 2012 by Heiko Carstens Committed by Martin Schwidefsky May 16, 2012

s390/pfault: add sanity check



If the task that was found on an initial interrupt doesn't match the
current task execute a WARN_ON_ONCE() and don't put the task to sleep.

When this happened something went wrong between the interface of the
hypervisor and the kernel. In such a case keep the tasks alive to
avoid a hanging system.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent 0a16ba78

arch/s390/mm/fault.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -584,6 +584,8 @@ static void pfault_interrupt(struct ext_code ext_code,
		}
		} else {
		/* signal bit not set -> a real page is missing. */
		if (WARN_ON_ONCE(tsk != current))
		goto out;
		if (tsk->thread.pfault_wait == 1) {
		/* Already on the list with a reference: put to sleep */
		__set_task_state(tsk, TASK_UNINTERRUPTIBLE);
		@@ -606,6 +608,7 @@ static void pfault_interrupt(struct ext_code ext_code,
		set_tsk_need_resched(tsk);
		}
		}
		out:
		spin_unlock(&pfault_lock);
		put_task_struct(tsk);
		}