diff options
| -rw-r--r-- | kernel/rcu/tree.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 7822a2e1370d..b9629cf08f94 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -376,16 +376,29 @@ static void __maybe_unused rcu_momentary_dyntick_idle(void) } /** - * rcu_is_cpu_rrupt_from_idle - see if idle or immediately interrupted from idle + * rcu_is_cpu_rrupt_from_idle - see if interrupted from idle * - * If the current CPU is idle or running at a first-level (not nested) + * If the current CPU is idle and running at a first-level (not nested) * interrupt from idle, return true. The caller must have at least * disabled preemption. */ static int rcu_is_cpu_rrupt_from_idle(void) { - return __this_cpu_read(rcu_data.dynticks_nesting) <= 0 && - __this_cpu_read(rcu_data.dynticks_nmi_nesting) <= 1; + /* Called only from within the scheduling-clock interrupt */ + lockdep_assert_in_irq(); + + /* Check for counter underflows */ + RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) < 0, + "RCU dynticks_nesting counter underflow!"); + RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) <= 0, + "RCU dynticks_nmi_nesting counter underflow/zero!"); + + /* Are we at first interrupt nesting level? */ + if (__this_cpu_read(rcu_data.dynticks_nmi_nesting) != 1) + return false; + + /* Does CPU appear to be idle from an RCU standpoint? */ + return __this_cpu_read(rcu_data.dynticks_nesting) == 0; } #define DEFAULT_RCU_BLIMIT 10 /* Maximum callbacks per rcu_do_batch. */ |