Re: [PATCH] arm64: smp: Fix missing IPI statistics

[Will Deacon <will@kernel.org>]

On Fri, Jun 07, 2024 at 03:47:16PM +0800, Jinjie Ruan wrote:
> commit 83cfac95c018 ("genirq: Allow interrupts to be excluded from
> /proc/interrupts") is to avoid IPIs appear twice in /proc/interrupts.
> But the commit 331a1b3a836c ("arm64: smp: Add arch support for backtrace
> using pseudo-NMI") and commit 2f5cd0c7ffde("arm64: kgdb: Implement
> kgdb_roundup_cpus() to enable pseudo-NMI roundup") set CPU_BACKTRACE and
> KGDB_ROUNDUP IPIs "IRQ_HIDDEN" flag but not show them in
> arch_show_interrupts(), which cause the interrupt kstat_irqs accounting
> is missing in display.
> 
> Fixes: 331a1b3a836c ("arm64: smp: Add arch support for backtrace using pseudo-NMI")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>  arch/arm64/kernel/smp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 31c8b3094dd7..7f9a5cf0f3b8 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -1039,7 +1039,8 @@ void __init set_smp_ipi_range(int ipi_base, int n)
>  		}
>  
>  		ipi_desc[i] = irq_to_desc(ipi_base + i);
> -		irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
> +		if (i < NR_IPI)
> +			irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
>  	}

Please can you show the contents of /proc/interrupts before and after
this patch and put that in the commit message? I'm not seeing how the
two new IPIs get picked up by arch_show_interrupts().

Thanks,

Will