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tracing: WARN on rcuidle

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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@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195541.416110581@infradead.org
This commit is contained in:
Peter Zijlstra 2023-01-12 20:43:48 +01:00 committed by Ingo Molnar
parent dc7305606d
commit 408b961146
2 changed files with 16 additions and 2 deletions
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15
include/linux/tracepoint.h
View File

@ -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(); \

3
kernel/trace/trace.c
View File

@ -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