lockdep: Fix lock_is_held() on recursion
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Mon, 6 Jun 2011 10:32:43 +0000 (12:32 +0200)
committerIngo Molnar <mingo@elte.hu>
Tue, 7 Jun 2011 10:25:50 +0000 (12:25 +0200)
commitf2513cde93f0957d5dc6c09bc24b0cccd27d8e1d
treeb461cb0836170eb555b20818802c121c79e76d33
parentf339b9dc1f03591761d5d930800db24bc0eda1e1
lockdep: Fix lock_is_held() on recursion

The main lock_is_held() user is lockdep_assert_held(), avoid false
assertions in lockdep_off() sections by unconditionally reporting the
lock is taken.

[ the reason this is important is a lockdep_assert_held() in ttwu()
  which triggers a warning under lockdep_off() as in printk() which
  can trigger another wakeup and lock up due to spinlock
  recursion, as reported and heroically debugged by Arne Jansen ]

Reported-and-tested-by: Arne Jansen <lists@die-jansens.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/1307398759.2497.966.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/lockdep.c