Tracepoints require that RCU is watching. To prevent them from being used in places that RCU is not watching, the trace_##event() macro always calls rcu_is_watching() even when the event is not enabled and warns if RCU is not watching. This is to make sure a warning is triggered even if the tracepoint is never enabled (as it is only a bug when it is). It was noticed that tracepoints could be hidden within trace_#event#_enabled() calls, which are used to do extra work for the tracepoint only if the tracepoint is enabled. But this also can hide the fact that a tracepoint is placed in a location that can be called when RCU is not watching. Commit 9764e731ef6ab ("tracepoint: Add lockdep rcu_is_watching() check to trace_##name##_enabled()") added a check to the trace_##event##_enabled() macro to make sure RCU is watching when it is called to make sure not to hide the bug of a tracepoint being called when RCU is not watching. There is one case in the irq_disable tracepoint where it is within a trace_irq_disable_enabled() block, but it checks if RCU is watching, and if it isn't, it makes a call to ct_irq_enter() that makes RCU watch again. But because trace_irq_disable_enabled() now checks if RCU is watching and will trigger if it isn't. This is a false warning as the code within the block handles this case. Add a new internal macro __trace_##event##_enabled() that doesn't check if RCU is watching, and convert the irq_enable/disable tracepoints over to it.
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| @@ -292,13 +292,18 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) · 291 unmodified lines | ||
| 292 | 292 | { \ |
| 293 | 293 | } \ |
| 294 | 294 | static inline bool \ |
| 295 | + __trace_##name##_enabled(void) \ | |
| 296 | + { \ | |
| 297 | + return static_branch_unlikely(&__tracepoint_##name.key);\ | |
| 298 | + } \ | |
| 299 | + static inline bool \ | |
| 295 | 300 | trace_##name##_enabled(void) \ |
| 296 | 301 | { \ |
| 297 | 302 | if (IS_ENABLED(CONFIG_LOCKDEP)) { \ |
| 298 | 303 | WARN_ONCE(!rcu_is_watching(), \ |
| 299 | 304 | "RCU not watching for tracepoint"); \ |
| 300 | 305 | } \ |
| 301 | − return static_branch_unlikely(&__tracepoint_##name.key);\ | |
| 306 | + return __trace_##name##_enabled(); \ | |
| 302 | 307 | } |
| 303 | 308 | |
| 304 | 309 | #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ |
| @@ -457,6 +462,11 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) · 152 unmodified lines | ||
| 457 | 462 | { \ |
| 458 | 463 | } \ |
| 459 | 464 | static inline bool \ |
| 465 | + __trace_##name##_enabled(void) \ | |
| 466 | + { \ | |
| 467 | + return false; \ | |
| 468 | + } \ | |
| 469 | + static inline bool \ | |
| 460 | 470 | trace_##name##_enabled(void) \ |
| 461 | 471 | { \ |
| 462 | 472 | return false; \ |