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Commit 4e49226e authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
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powerpc/watchdog: provide more data in watchdog messages 



Provide timebase and timebase of last heartbeat in watchdog lockup
messages. Also provide a stack trace of when a CPU becomes un-stuck,
which can be useful -- it could be where irqs are re-enabled, so it
may be the end of the critical section which is responsible for the
latency which is useful information.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 5a951c4e

arch/powerpc/kernel/watchdog.c

+25 −3
Original line number Diff line number Diff line
@@ -111,7 +111,13 @@ static inline void wd_smp_unlock(unsigned long *flags) 


static void wd_lockup_ipi(struct pt_regs *regs)

{

	pr_emerg("CPU %d Hard LOCKUP\n", raw_smp_processor_id());

	int cpu = raw_smp_processor_id();

	u64 tb = get_tb();



	pr_emerg("CPU %d Hard LOCKUP\n", cpu);

	pr_emerg("CPU %d TB:%lld, last heartbeat TB:%lld (%lldms ago)\n",

		 cpu, tb, per_cpu(wd_timer_tb, cpu),

		 tb_to_ns(tb - per_cpu(wd_timer_tb, cpu)) / 1000000);

	print_modules();

	print_irqtrace_events(current);

	if (regs)
@@ -154,6 +160,9 @@ static void watchdog_smp_panic(int cpu, u64 tb) 


	pr_emerg("CPU %d detected hard LOCKUP on other CPUs %*pbl\n",

		 cpu, cpumask_pr_args(&wd_smp_cpus_pending));

	pr_emerg("CPU %d TB:%lld, last SMP heartbeat TB:%lld (%lldms ago)\n",

		 cpu, tb, wd_smp_last_reset_tb,

		 tb_to_ns(tb - wd_smp_last_reset_tb) / 1000000);



	if (!sysctl_hardlockup_all_cpu_backtrace) {

		/*
@@ -194,10 +203,19 @@ static void wd_smp_clear_cpu_pending(int cpu, u64 tb) 
{

	if (!cpumask_test_cpu(cpu, &wd_smp_cpus_pending)) {

		if (unlikely(cpumask_test_cpu(cpu, &wd_smp_cpus_stuck))) {

			struct pt_regs *regs = get_irq_regs();

			unsigned long flags;



			pr_emerg("CPU %d became unstuck\n", cpu);

			wd_smp_lock(&flags);



			pr_emerg("CPU %d became unstuck TB:%lld\n",

				 cpu, tb);

			print_irqtrace_events(current);

			if (regs)

				show_regs(regs);

			else

				dump_stack();



			cpumask_clear_cpu(cpu, &wd_smp_cpus_stuck);

			wd_smp_unlock(&flags);

		}
@@ -252,7 +270,11 @@ void soft_nmi_interrupt(struct pt_regs *regs) 
		}

		set_cpu_stuck(cpu, tb);



		pr_emerg("CPU %d self-detected hard LOCKUP @ %pS\n", cpu, (void *)regs->nip);

		pr_emerg("CPU %d self-detected hard LOCKUP @ %pS\n",

			 cpu, (void *)regs->nip);

		pr_emerg("CPU %d TB:%lld, last heartbeat TB:%lld (%lldms ago)\n",

			 cpu, tb, per_cpu(wd_timer_tb, cpu),

			 tb_to_ns(tb - per_cpu(wd_timer_tb, cpu)) / 1000000);

		print_modules();

		print_irqtrace_events(current);

		show_regs(regs);