Excerpts from Nicholas Piggin's message of November 10, 2021 12:50 pm:
> @@ -160,11 +187,26 @@ static void watchdog_smp_panic(int cpu, u64 tb)
> goto out;
> if (cpumask_test_cpu(cpu, &wd_smp_cpus_pending))
> goto out;
> - if (cpumask_weight(&wd_smp_cpus_pending) == 0)
> + if (!wd_try_report())
> goto out;
> + for_each_online_cpu(c) {
> + if (!cpumask_test_cpu(c, &wd_smp_cpus_pending))
> + continue;
> + if (c == cpu)
> + continue; // should not happen
> +
> + __cpumask_set_cpu(c, &wd_smp_cpus_ipi);
> + if (set_cpu_stuck(c, tb))
> + break;
> + }
> + if (cpumask_empty(&wd_smp_cpus_ipi)) {
> + wd_end_reporting();
> + goto out;
> + }
> + wd_smp_unlock(&flags);
>
> pr_emerg("CPU %d detected hard LOCKUP on other CPUs %*pbl\n",
> - cpu, cpumask_pr_args(&wd_smp_cpus_pending));
> + cpu, cpumask_pr_args(&wd_smp_cpus_ipi));
> 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);
Oops, this has a bug: wd_smp_last_reset_tb gets reset above by
set_cpu_stuck when all the stuck CPUs are taken out of the pending
mask, so this prints nonsense last-reset times.
I might just send out an updated series, because the fix has a slight
clash with the next patch. All I do is take a local copy of
wd_smp_last_reset_tb near the start of the function.
Thanks,
Nick
