From 408b961146be4c1a776ce285c3c289afab15298a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 12 Jan 2023 20:43:48 +0100 Subject: tracing: WARN on rcuidle 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) Signed-off-by: Ingo Molnar Tested-by: Tony Lindgren Tested-by: Ulf Hansson Acked-by: Rafael J. Wysocki Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20230112195541.416110581@infradead.org --- include/linux/tracepoint.h | 15 +++++++++++++-- kernel/trace/trace.c | 3 +++ 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 4b33b95eb8be..552f80b8362f 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -177,6 +177,17 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DO_TRACE_CALL(name, args) __traceiter_##name(NULL, args) #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 *tracepoint_ptr_deref(tracepoint_ptr_t *p) 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(); \ diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a555a861b978..54ec1592ac79 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3128,6 +3128,9 @@ void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, 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 -- cgit v1.2.3-70-g09d2