ARCH_WANTS_NO_INSTR (a superset of CONFIG_GENERIC_ENTRY) disallows any and all tracing when RCU isn't enabled. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Acked-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Tested-by: Tony Lindgren <tony@xxxxxxxxxxx> Tested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> --- include/linux/tracepoint.h | 15 +++++++++++++-- kernel/trace/trace.c | 3 +++ 2 files changed, 16 insertions(+), 2 deletions(-) --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -178,6 +178,17 @@ static inline struct tracepoint *tracepo #endif /* CONFIG_HAVE_STATIC_CALL */ /* + * ARCH_WANTS_NO_INSTR archs are expected to have sanitized entry and idle + * code that disallow any/all tracing/instrumentation when RCU isn't watching. + */ +#ifdef CONFIG_ARCH_WANTS_NO_INSTR +#define RCUIDLE_COND(rcuidle) (rcuidle) +#else +/* srcu can't be used from NMI */ +#define RCUIDLE_COND(rcuidle) (rcuidle && in_nmi()) +#endif + +/* * it_func[0] is never NULL because there is at least one element in the array * when the array itself is non NULL. */ @@ -188,8 +199,8 @@ static inline struct tracepoint *tracepo if (!(cond)) \ return; \ \ - /* srcu can't be used from NMI */ \ - WARN_ON_ONCE(rcuidle && in_nmi()); \ + if (WARN_ON_ONCE(RCUIDLE_COND(rcuidle))) \ + return; \ \ /* keep srcu and sched-rcu usage consistent */ \ preempt_disable_notrace(); \ --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3119,6 +3119,9 @@ void __trace_stack(struct trace_array *t return; } + if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY))) + return; + /* * When an NMI triggers, RCU is enabled via ct_nmi_enter(), * but if the above rcu_is_watching() failed, then the NMI
