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References: <20220714084136.570176-1-chenhuacai@loongson.cn> <20220714084136.570176-2-chenhuacai@loongson.cn>
In-Reply-To: <20220714084136.570176-2-chenhuacai@loongson.cn>
From:   Huacai Chen <chenhuacai@gmail.com>
Date:   Thu, 28 Jul 2022 20:42:35 +0800
Message-ID: <CAAhV-H7W8V8XdJXX5FvyvvSCAbeTSgLEKhHLivm89T-Nd59Umw@mail.gmail.com>
Subject: Re: [PATCH V2 2/3] LoongArch: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK
To:     Huacai Chen <chenhuacai@loongson.cn>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>, loongarch@lists.linux.dev,
        linux-arch <linux-arch@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, Guo Ren <guoren@kernel.org>,
        Xuerui Wang <kernel@xen0n.name>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        "open list:MIPS" <linux-mips@vger.kernel.org>,
        Linux-sh list <linux-sh@vger.kernel.org>,
        stable <stable@vger.kernel.org>
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Hi, Arnd,

Since the SH maintainer hasn't responded, I suppose it is better to
let both LoongArch fix and SH fix go through your asm-generic tree?

Huacai

On Thu, Jul 14, 2022 at 4:41 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
>
> When CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS is selected,
> cpu_max_bits_warn() generates a runtime warning similar as below while
> we show /proc/cpuinfo. Fix this by using nr_cpu_ids (the runtime limit)
> instead of NR_CPUS to iterate CPUs.
>
> [    3.052463] ------------[ cut here ]------------
> [    3.059679] WARNING: CPU: 3 PID: 1 at include/linux/cpumask.h:108 show_cpuinfo+0x5e8/0x5f0
> [    3.070072] Modules linked in: efivarfs autofs4
> [    3.076257] CPU: 0 PID: 1 Comm: systemd Not tainted 5.19-rc5+ #1052
> [    3.084034] Hardware name: Loongson Loongson-3A5000-7A1000-1w-V0.1-CRB/Loongson-LS3A5000-7A1000-1w-EVB-V1.21, BIOS Loongson-UDK2018-V2.0.04082-beta7 04/27
> [    3.099465] Stack : 9000000100157b08 9000000000f18530 9000000000cf846c 9000000100154000
> [    3.109127]         9000000100157a50 0000000000000000 9000000100157a58 9000000000ef7430
> [    3.118774]         90000001001578e8 0000000000000040 0000000000000020 ffffffffffffffff
> [    3.128412]         0000000000aaaaaa 1ab25f00eec96a37 900000010021de80 900000000101c890
> [    3.138056]         0000000000000000 0000000000000000 0000000000000000 0000000000aaaaaa
> [    3.147711]         ffff8000339dc220 0000000000000001 0000000006ab4000 0000000000000000
> [    3.157364]         900000000101c998 0000000000000004 9000000000ef7430 0000000000000000
> [    3.167012]         0000000000000009 000000000000006c 0000000000000000 0000000000000000
> [    3.176641]         9000000000d3de08 9000000001639390 90000000002086d8 00007ffff0080286
> [    3.186260]         00000000000000b0 0000000000000004 0000000000000000 0000000000071c1c
> [    3.195868]         ...
> [    3.199917] Call Trace:
> [    3.203941] [<90000000002086d8>] show_stack+0x38/0x14c
> [    3.210666] [<9000000000cf846c>] dump_stack_lvl+0x60/0x88
> [    3.217625] [<900000000023d268>] __warn+0xd0/0x100
> [    3.223958] [<9000000000cf3c90>] warn_slowpath_fmt+0x7c/0xcc
> [    3.231150] [<9000000000210220>] show_cpuinfo+0x5e8/0x5f0
> [    3.238080] [<90000000004f578c>] seq_read_iter+0x354/0x4b4
> [    3.245098] [<90000000004c2e90>] new_sync_read+0x17c/0x1c4
> [    3.252114] [<90000000004c5174>] vfs_read+0x138/0x1d0
> [    3.258694] [<90000000004c55f8>] ksys_read+0x70/0x100
> [    3.265265] [<9000000000cfde9c>] do_syscall+0x7c/0x94
> [    3.271820] [<9000000000202fe4>] handle_syscall+0xc4/0x160
> [    3.281824] ---[ end trace 8b484262b4b8c24c ]---
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  arch/loongarch/kernel/proc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/loongarch/kernel/proc.c b/arch/loongarch/kernel/proc.c
> index e0b5f3b031b1..b12a1f21f864 100644
> --- a/arch/loongarch/kernel/proc.c
> +++ b/arch/loongarch/kernel/proc.c
> @@ -106,7 +106,7 @@ static void *c_start(struct seq_file *m, loff_t *pos)
>  {
>         unsigned long i = *pos;
>
> -       return i < NR_CPUS ? (void *)(i + 1) : NULL;
> +       return i < nr_cpu_ids ? (void *)(i + 1) : NULL;
>  }
>
>  static void *c_next(struct seq_file *m, void *v, loff_t *pos)
> --
> 2.31.1
>