diff options
author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-06-06 12:32:43 +0200 |
---|---|---|
committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2012-05-17 11:20:45 -0400 |
commit | 573289be5cd6084124341eee86c6494528e9825c (patch) | |
tree | 75307e70b0ae36f05239cd64f2eedad2d50da53b /kernel | |
parent | 064a930ea49c1c420c45f8b0db9b0609c5aa3047 (diff) |
lockdep: Fix lock_is_held() on recursion
commit f2513cde93f0957d5dc6c09bc24b0cccd27d8e1d upstream.
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>
Link: http://lkml.kernel.org/r/1307398759.2497.966.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/lockdep.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 2594e1ce41cb..157145223f11 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3240,7 +3240,7 @@ int lock_is_held(struct lockdep_map *lock) int ret = 0; if (unlikely(current->lockdep_recursion)) - return ret; + return 1; /* avoid false negative lockdep_assert_held() */ raw_local_irq_save(flags); check_flags(flags); |