In mark_lock_irq(), the following checks are performed: ---------------------------------- | -> | unsafe | read unsafe | |----------------------------------| | safe | F B | F* B* | |----------------------------------| | read safe | F? B* | - | ----------------------------------
Where: F: check_usage_forwards B: check_usage_backwards *: check enabled by STRICT_READ_CHECKS ?: check enabled by the !dir condition >From checking point of view, the special F? case does not make sense, whereas it perhaps is made for peroformance concern. As later patch will address this issue, remove this exception, which makes the checks consistent later. With STRICT_READ_CHECKS = 1 which is default, there is no functional change. Signed-off-by: Yuyang Du <[email protected]> --- kernel/locking/lockdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 1b78216..2f24028 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3149,7 +3149,7 @@ typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, * Validate that the lock dependencies don't have conflicting usage * states. */ - if ((!read || !dir || STRICT_READ_CHECKS) && + if ((!read || STRICT_READ_CHECKS) && !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK))) return 0; -- 1.8.3.1
