diff options
Diffstat (limited to 'include/linux/tracepoint.h')
| -rw-r--r-- | include/linux/tracepoint.h | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 4b33b95eb8be..6811e43c1b5c 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -178,6 +178,17 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #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(); \ @@ -231,12 +242,11 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * not add unwanted padding between the beginning of the section and the * structure. Force alignment to the same alignment as the section start. * - * When lockdep is enabled, we make sure to always do the RCU portions of - * the tracepoint code, regardless of whether tracing is on. However, - * don't check if the condition is false, due to interaction with idle - * instrumentation. This lets us find RCU issues triggered with tracepoints - * even when this tracepoint is off. This code has no purpose other than - * poking RCU a bit. + * When lockdep is enabled, we make sure to always test if RCU is + * "watching" regardless if the tracepoint is enabled or not. Tracepoints + * require RCU to be active, and it should always warn at the tracepoint + * site if it is not watching, as it will need to be active when the + * tracepoint is enabled. */ #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ extern int __traceiter_##name(data_proto); \ @@ -249,9 +259,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) TP_ARGS(args), \ TP_CONDITION(cond), 0); \ if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ - rcu_read_lock_sched_notrace(); \ - rcu_dereference_sched(__tracepoint_##name.funcs);\ - rcu_read_unlock_sched_notrace(); \ + WARN_ON_ONCE(!rcu_is_watching()); \ } \ } \ __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \ @@ -471,7 +479,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * * This is how the trace record is structured and will * * be saved into the ring buffer. These are the fields * * that will be exposed to user-space in - * * /sys/kernel/debug/tracing/events/<*>/format. + * * /sys/kernel/tracing/events/<*>/format. * * * * The declared 'local variable' is called '__entry' * * @@ -531,7 +539,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * tracepoint callback (this is used by programmatic plugins and * can also by used by generic instrumentation like SystemTap), and * it is also used to expose a structured trace record in - * /sys/kernel/debug/tracing/events/. + * /sys/kernel/tracing/events/. * * A set of (un)registration functions can be passed to the variant * TRACE_EVENT_FN to perform any (un)registration work. |