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) <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Tested-by: Tony Lindgren <[email protected]> Tested-by: Ulf Hansson <[email protected]> Acked-by: Rafael J. Wysocki <[email protected]> Acked-by: Frederic Weisbecker <[email protected]> Link: https://lore.kernel.org/r/[email protected]
wafgo · Jan 13, 2023 · 408b961 · 408b961
1 parent dc73056
commit 408b961
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Showing 2 changed files with 16 additions and 2 deletions.
diff --git 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
@@ -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
-Original file line number
+Diff line change
@@ Expand Up @@
     		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
@@ Expand Down @@