[PATCH] lockdep: s390 turn validator off in machine-check handler

Machine checks on s390 are always enabled (except in the machine check handler
itself).  Therefore use lockdep_off()/on() in the machine check handler to
avoid deadlocks in the lock validator.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>