d5b5f391d4
Vince's perf-trinity fuzzer found yet another 'interesting' problem. When we sample the irq_work_exit tracepoint with period==1 (or PERF_SAMPLE_PERIOD) and we add an fasync SIGNAL handler we create an infinite event generation loop: ,-> <IPI> | irq_work_exit() -> | trace_irq_work_exit() -> | ... | __perf_event_overflow() -> (due to fasync) | irq_work_queue() -> (irq_work_list must be empty) '--------- arch_irq_work_raise() Similar things can happen due to regular poll() wakeups if we exceed the ring-buffer wakeup watermark, or have an event_limit. To avoid this, dis-allow sampling this particular tracepoint. In order to achieve this, create a special perf_perm function pointer for each event and call this (when set) on trying to create a tracepoint perf event. [ roasted: use expr... to allow for ',' in your expression ] Reported-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Dave Jones <davej@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20131114152304.GC5364@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
#undef TRACE_SYSTEM
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#define TRACE_SYSTEM irq_vectors
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#if !defined(_TRACE_IRQ_VECTORS_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_IRQ_VECTORS_H
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#include <linux/tracepoint.h>
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extern void trace_irq_vector_regfunc(void);
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extern void trace_irq_vector_unregfunc(void);
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DECLARE_EVENT_CLASS(x86_irq_vector,
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TP_PROTO(int vector),
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TP_ARGS(vector),
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TP_STRUCT__entry(
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__field( int, vector )
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),
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TP_fast_assign(
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__entry->vector = vector;
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),
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TP_printk("vector=%d", __entry->vector) );
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#define DEFINE_IRQ_VECTOR_EVENT(name) \
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DEFINE_EVENT_FN(x86_irq_vector, name##_entry, \
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TP_PROTO(int vector), \
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TP_ARGS(vector), \
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trace_irq_vector_regfunc, \
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trace_irq_vector_unregfunc); \
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DEFINE_EVENT_FN(x86_irq_vector, name##_exit, \
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TP_PROTO(int vector), \
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TP_ARGS(vector), \
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trace_irq_vector_regfunc, \
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trace_irq_vector_unregfunc);
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/*
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* local_timer - called when entering/exiting a local timer interrupt
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* vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(local_timer);
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/*
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* reschedule - called when entering/exiting a reschedule vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(reschedule);
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/*
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* spurious_apic - called when entering/exiting a spurious apic vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(spurious_apic);
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/*
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* error_apic - called when entering/exiting an error apic vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(error_apic);
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/*
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* x86_platform_ipi - called when entering/exiting a x86 platform ipi interrupt
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* vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(x86_platform_ipi);
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/*
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* irq_work - called when entering/exiting a irq work interrupt
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* vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(irq_work);
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/*
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* We must dis-allow sampling irq_work_exit() because perf event sampling
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* itself can cause irq_work, which would lead to an infinite loop;
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*
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* 1) irq_work_exit happens
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* 2) generates perf sample
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* 3) generates irq_work
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* 4) goto 1
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*/
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TRACE_EVENT_PERF_PERM(irq_work_exit, is_sampling_event(p_event) ? -EPERM : 0);
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/*
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* call_function - called when entering/exiting a call function interrupt
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* vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(call_function);
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/*
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* call_function_single - called when entering/exiting a call function
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* single interrupt vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(call_function_single);
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/*
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* threshold_apic - called when entering/exiting a threshold apic interrupt
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* vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(threshold_apic);
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/*
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* thermal_apic - called when entering/exiting a thermal apic interrupt
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* vector handler
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*/
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DEFINE_IRQ_VECTOR_EVENT(thermal_apic);
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#undef TRACE_INCLUDE_PATH
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#define TRACE_INCLUDE_PATH .
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#define TRACE_INCLUDE_FILE irq_vectors
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#endif /* _TRACE_IRQ_VECTORS_H */
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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