On Tue, 20 Jun 2017 12:49:25 +0530
Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx> wrote:
> Hi,
>
> commit: 347de24 (powerpc/64s: implement arch-specific hardlockup
> watchdog)
>
> linux-next fails to boot on PowerPC Bare-metal box.
>
> Test: boot
> Machine type: Power 8 Bare-metal
> Kernel: 4.12.0-rc5-next-20170619
> gcc: version 4.8.5
>
>
> In file arch/powerpc/kernel/watchdog.c
>
> void soft_nmi_interrupt(struct pt_regs *regs)
> {
> unsigned long flags;
> int cpu = raw_smp_processor_id();
> u64 tb;
>
> if (!cpumask_test_cpu(cpu, &wd_cpus_enabled))
> return;
>
> >>> nmi_enter();
Thanks for the report.
This is due to emergency stacks not zeroing preempt_count, so they get
garbage here, and it just trips the BUG_ON(in_nmi()) check.
Don't think it's a bug in the proposed new powerpc watchdog. (at least
I was able to reproduce your bug and fix it by fixing the stack init).
Thanks,
Nick
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