Re: [PATCH v4 -next 14/15] sh: vdso: move the sysctl to arch/sh/kernel/vsyscall/vsyscall.c

[yukaixiong <yukaixiong@huawei.com>]

On 2025/1/3 19:11, Geert Uytterhoeven wrote:
> Hi Kaixiong,
>
> On Sat, Dec 28, 2024 at 4:07 PM Kaixiong Yu <yukaixiong@huawei.com> wrote:
>> When CONFIG_SUPERH and CONFIG_VSYSCALL are defined,
>> vdso_enabled belongs to arch/sh/kernel/vsyscall/vsyscall.c.
>> So, move it into its own file. After this patch is applied,
>> all sysctls of vm_table would be moved. So, delete vm_table.
>>
>> Signed-off-by: Kaixiong Yu <yukaixiong@huawei.com>
>> Reviewed-by: Kees Cook <kees@kernel.org>
>> ---
>> v4:
>>   - const qualify struct ctl_table vdso_table
> Thanks for your patch!
>
> I gave this a try on landisk, and /proc/sys/vm/vdso_enabled
> disappeared.
>
>> --- a/arch/sh/kernel/vsyscall/vsyscall.c
>> +++ b/arch/sh/kernel/vsyscall/vsyscall.c
>> @@ -55,6 +67,8 @@ int __init vsyscall_init(void)
>>                 &vsyscall_trapa_start,
>>                 &vsyscall_trapa_end - &vsyscall_trapa_start);
>>
>> +       register_sysctl_init("vm", vdso_table);
>      "failed when register_sysctl_sz vdso_table to vm"
>
> Adding some debug prints shows that kzalloc() in
> __register_sysctl_table() fails, presumably because it is called too
> early in the boot process.
>
>> +
>>          return 0;
>>   }
> Moving the call to register_sysctl_init() into its own fs_initcall(),
> like the gmail-whitespace-damaged patch below, fixes that.
>
> --- a/arch/sh/kernel/vsyscall/vsyscall.c
> +++ b/arch/sh/kernel/vsyscall/vsyscall.c
> @@ -67,11 +67,17 @@ int __init vsyscall_init(void)
>                 &vsyscall_trapa_start,
>                 &vsyscall_trapa_end - &vsyscall_trapa_start);
>
> -       register_sysctl_init("vm", vdso_table);
> +       return 0;
> +}
>
> +static int __init vm_sysctl_init(void)
> +{
> +       register_sysctl_init("vm", vdso_table);
>          return 0;
>   }
>
> +fs_initcall(vm_sysctl_init);
> +
>   /* Setup a VMA at program startup for the vsyscall page */
>   int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>   {
>
> Gr{oetje,eeting}s,
>
>                          Geert

Thank you so much for your test and fix patch !

I will fix it in patches series v5.

Best ...