There is no reason not to always, accurately, track IRQ state. This change also makes IRQ state tracking ignore lockdep_off().
Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- kernel/locking/lockdep.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3646,7 +3646,12 @@ static void __trace_hardirqs_on_caller(v */ void lockdep_hardirqs_on_prepare(unsigned long ip) { - if (unlikely(!debug_locks || current->lockdep_recursion)) + /* + * Even though NMIs can happen while in lockdep; we only call this + * then the NMI returns to an IRQs enabled context, which guarantees + * we're not in lockdep. + */ + if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion & LOCKDEP_RECURSION_MASK)) return; if (unlikely(lockdep_hardirqs_enabled())) { @@ -3682,9 +3687,11 @@ void lockdep_hardirqs_on_prepare(unsigne current->hardirq_chain_key = current->curr_chain_key; - current->lockdep_recursion++; - __trace_hardirqs_on_caller(); - lockdep_recursion_finish(); + if (!in_nmi()) { + current->lockdep_recursion++; + __trace_hardirqs_on_caller(); + lockdep_recursion_finish(); + } } EXPORT_SYMBOL_GPL(lockdep_hardirqs_on_prepare); @@ -3692,7 +3699,7 @@ void noinstr lockdep_hardirqs_on(unsigne { struct task_struct *curr = current; - if (unlikely(!debug_locks || curr->lockdep_recursion)) + if (DEBUG_LOCKS_WARN_ON(curr->lockdep_recursion & LOCKDEP_RECURSION_MASK)) return; if (lockdep_hardirqs_enabled()) { @@ -3735,8 +3742,10 @@ void noinstr lockdep_hardirqs_off(unsign { struct task_struct *curr = current; - if (unlikely(!debug_locks || curr->lockdep_recursion)) - return; + /* + * Can't test recursion; NMIs can happen while in lockdep. + * Harmless though; all we do is clear hardirqs_enabled. + */ /* * So we're supposed to get called after you mask local IRQs, but for
