From: Will Deacon <will@kernel.org>
To: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Cc: Mark Rutland <mark.rutland@arm.com>,
catalin.marinas@arm.com,
"Signed-off-by : Gavin Shan" <gshan@redhat.com>,
Yuji Ishikawa <yuji2.ishikawa@toshiba.co.jp>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH/RFC] arm64/kernel: Fix return value when cpu_online() fails in __cpu_up()
Date: Thu, 28 May 2020 09:12:04 +0100 [thread overview]
Message-ID: <20200528081204.GC22156@willie-the-truck> (raw)
In-Reply-To: <20200527233457.2531118-1-nobuhiro1.iwamatsu@toshiba.co.jp>
On Thu, May 28, 2020 at 08:34:57AM +0900, Nobuhiro Iwamatsu wrote:
> If boot_secondary() was successful, and cpu_online() was an error in
> __cpu_up(), -EIO was returned, but 0 is returned by commit d22b115cbfbb7
> ("arm64/kernel: Simplify __cpu_up() by bailing out early").
> Therefore, bringup_wait_for_ap() causes the primary core to wait for a
> long time, which may cause boot failure.
> This commit sets -EIO to return code under the same conditions.
>
> Fixes: d22b115cbfbb7 ("arm64/kernel: Simplify __cpu_up() by bailing out early")
> CC: Signed-off-by: Gavin Shan <gshan@redhat.com>
> CC: Catalin Marinas <catalin.marinas@arm.com>
> CC: Mark Rutland <mark.rutland@arm.com>
> Tested-by: Yuji Ishikawa <yuji2.ishikawa@toshiba.co.jp>
> Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
> ---
> arch/arm64/kernel/smp.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 061f60fe452f7..ea677680e4277 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -137,6 +137,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
> if (cpu_online(cpu))
> return 0;
>
> + ret = -EIO;
> pr_crit("CPU%u: failed to come online\n", cpu);
> secondary_data.task = NULL;
> secondary_data.stack = NULL;
This appears to restore the old behaviour, so looks good to me. I'd probably
just replace the final 'return ret' with 'return -EIO' since it's never
going to be anything else.
Also -- aren't you in a pretty serious mess if the CPU starts but doesn't
come online? I think the patch is fine, but this really shouldn't happen,
right? Could you share your dmesg?
Either way:
Acked-by: Will Deacon <will@kernel.org>
Catalin -- do you want to take this (the problematic change was introduced
during the last merge window afaict)?
Will
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next prev parent reply other threads:[~2020-05-28 8:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 23:34 [PATCH/RFC] arm64/kernel: Fix return value when cpu_online() fails in __cpu_up() Nobuhiro Iwamatsu
2020-05-28 8:12 ` Will Deacon [this message]
2020-05-28 23:31 ` nobuhiro1.iwamatsu
2020-05-28 11:53 ` Catalin Marinas
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