From: Atish Patra <atish.patra@wdc.com>
To: Christopher Lameter <cl@linux.com>
Cc: "linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
Albert Ou <aou@eecs.berkeley.edu>,
Jason Cooper <jason@lakedaemon.net>,
Alan Kao <alankao@andestech.com>,
Dmitriy Cherkasov <dmitriy@oss-tech.org>,
Anup Patel <anup@brainfault.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Johan Hovold <johan@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Palmer Dabbelt <palmer@sifive.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Andreas Schwab <schwab@suse.de>,
Marc Zyngier <marc.zyngier@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Guenter Roeck <linux@roeck-us.net>
Subject: Re: [v5 PATCH 5/8] RISC-V: Compare cpuid with NR_CPUS before mapping.
Date: Thu, 14 Feb 2019 15:33:22 -0800 [thread overview]
Message-ID: <e86e8239-bea8-b11f-f09b-63110ec16d88@wdc.com> (raw)
In-Reply-To: <01000168ed298ba3-fea3ca2b-436b-4ce6-a0df-cebe727bf55c-000000@email.amazonses.com>
On 2/14/19 9:59 AM, Christopher Lameter wrote:
> On Wed, 13 Feb 2019, Atish Patra wrote:
>
>> --- a/arch/riscv/kernel/smpboot.c
>> +++ b/arch/riscv/kernel/smpboot.c
>> @@ -66,6 +66,11 @@ void __init setup_smp(void)
>> found_boot_cpu = 1;
>> continue;
>> }
>> + if (cpuid >= NR_CPUS) {
>
> Use nr_cpu_ids instead? Its initialized to NR_CPUS but can be restricted
> if we can determine on boot how many processor we truly have.
>
nr_cpu_ids can be modified by nr_cpus in boot command line. If nr_cpus
is set to a value less than number of cpus described in the DT, kernel
may not boot depending on the boot hartid. This happens because we break
out of the while loop and BUG_ON(!found_boot_cpu).
As the required fix will be different from the current fix, I would like
to do this in a follow up patch if that's ok.
Btw, thanks for bringing this up.
Regards,
Atish
next prev parent reply other threads:[~2019-02-14 23:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-13 20:18 [v5 PATCH 0/8] Various SMP related fixes Atish Patra
2019-02-13 20:18 ` [v5 PATCH 1/8] RISC-V: Do not wait indefinitely in __cpu_up Atish Patra
2019-02-13 20:18 ` [v5 PATCH 2/8] RISC-V: Move cpuid to hartid mapping to SMP Atish Patra
2019-02-13 20:18 ` [v5 PATCH 3/8] RISC-V: Remove NR_CPUs check during hartid search from DT Atish Patra
2019-02-13 20:18 ` [v5 PATCH 4/8] RISC-V: Allow hartid-to-cpuid function to fail Atish Patra
2019-02-13 20:18 ` [v5 PATCH 5/8] RISC-V: Compare cpuid with NR_CPUS before mapping Atish Patra
2019-02-14 17:59 ` Christopher Lameter
2019-02-14 23:33 ` Atish Patra [this message]
2019-02-13 20:18 ` [v5 PATCH 6/8] clocksource/drivers/riscv: Add required checks during clock source init Atish Patra
2019-02-14 10:24 ` Daniel Lezcano
2019-02-14 18:21 ` Atish Patra
2019-02-13 20:18 ` [v5 PATCH 7/8] irqchip/irq-sifive-plic: Check and continue in case of an invalid cpuid Atish Patra
2019-02-13 20:18 ` [v5 PATCH 8/8] RISC-V: Assign hwcap as per comman capabilities Atish Patra
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