add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/lib/nmi_backtrace.c
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@@ -85,12 +85,16 @@
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 	put_cpu();
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 }
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+// Dump stacks even for idle CPUs.
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+static bool backtrace_idle;
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+module_param(backtrace_idle, bool, 0644);
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+
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 bool nmi_cpu_backtrace(struct pt_regs *regs)
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 {
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 	int cpu = smp_processor_id();
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 	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
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-		if (regs && cpu_in_idle(instruction_pointer(regs))) {
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+		if (!READ_ONCE(backtrace_idle) && regs && cpu_in_idle(instruction_pointer(regs))) {
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 			pr_warn("NMI backtrace for cpu %d skipped: idling at %pS\n",
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 				cpu, (void *)instruction_pointer(regs));
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 		} else {