x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt() (4787c368) · Commits · 戴 / test

Reschedule vector tracepoints may be called in cpu idle state. This causes lockdep check warning below. The tracepoint requires rcu but for accuracy it also requires irq_enter() (tracepoints record the irq context), thus, the tracepoint interrupt handler should be calling irq_enter() and not rcu_irq_enter() (irq_enter() calls rcu_irq_enter()). So, add irq_enter/exit() to smp_trace_reschedule_interrupt() with common pre/post processing functions, smp_entering_irq() and exiting_irq() (exiting_irq() calls just irq_exit() in arch/x86/include/asm/apic.h), because these can be shared among reschedule, call_function, and call_function_single vectors. [ 50.720557] Testing event reschedule_exit: [ 50.721349] [ 50.721502] =============================== [ 50.721835] [ INFO: suspicious RCU usage. ] [ 50.722169] 3.10.0-rc6-00004-gcf910e8 #190 Not tainted [ 50.722582] ------------------------------- [ 50.722915] /c/kernel-tests/src/linux/arch/x86/include/asm/trace/irq_vectors.h:50 suspicious rcu_dereference_check() usage! [ 50.723770] [ 50.723770] other info that might help us debug this: [ 50.723770] [ 50.724385] [ 50.724385] RCU used illegally from idle CPU! [ 50.724385] rcu_scheduler_active = 1, debug_locks = 0 [ 50.725232] RCU used illegally from extended quiescent state! [ 50.725690] no locks held by swapper/0/0. [ 50.726010] [ 50.726010] stack backtrace: [...] Signed-off-by:

Seiji Aguchi <seiji.aguchi@hds.com> Reviewed-by:

Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/51CDCFA3.9080101@hds.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/smp.c

+18 −11

Original line number	Diff line number	Diff line
		@@ -265,23 +265,30 @@ void smp_reschedule_interrupt(struct pt_regs *regs)
		*/
		}

		void smp_trace_reschedule_interrupt(struct pt_regs *regs)
		static inline void smp_entering_irq(void)
		{
		ack_APIC_irq();
		irq_enter();
		}

		void smp_trace_reschedule_interrupt(struct pt_regs *regs)
		{
		/*
		* Need to call irq_enter() before calling the trace point.
		* __smp_reschedule_interrupt() calls irq_enter/exit() too (in
		* scheduler_ipi(). This is OK, since those functions are allowed
		* to nest.
		*/
		smp_entering_irq();
		trace_reschedule_entry(RESCHEDULE_VECTOR);
		__smp_reschedule_interrupt();
		trace_reschedule_exit(RESCHEDULE_VECTOR);
		exiting_irq();
		/*
		* KVM uses this interrupt to force a cpu out of guest mode
		*/
		}

		static inline void call_function_entering_irq(void)
		{
		ack_APIC_irq();
		irq_enter();
		}

		static inline void __smp_call_function_interrupt(void)
		{
		generic_smp_call_function_interrupt();
		@@ -290,14 +297,14 @@ static inline void __smp_call_function_interrupt(void)

		void smp_call_function_interrupt(struct pt_regs *regs)
		{
		call_function_entering_irq();
		smp_entering_irq();
		__smp_call_function_interrupt();
		exiting_irq();
		}

		void smp_trace_call_function_interrupt(struct pt_regs *regs)
		{
		call_function_entering_irq();
		smp_entering_irq();
		trace_call_function_entry(CALL_FUNCTION_VECTOR);
		__smp_call_function_interrupt();
		trace_call_function_exit(CALL_FUNCTION_VECTOR);
		@@ -312,14 +319,14 @@ static inline void __smp_call_function_single_interrupt(void)

		void smp_call_function_single_interrupt(struct pt_regs *regs)
		{
		call_function_entering_irq();
		smp_entering_irq();
		__smp_call_function_single_interrupt();
		exiting_irq();
		}

		void smp_trace_call_function_single_interrupt(struct pt_regs *regs)
		{
		call_function_entering_irq();
		smp_entering_irq();
		trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
		__smp_call_function_single_interrupt();
		trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);

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