Re: [PATCH V2 3/3] SH: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK

Hi Adrian

On 9/27/2024 5:06 PM, John Paul Adrian Glaubitz wrote:
> Hi,
> 
> On Fri, 2024-09-27 at 13:31 +0800, Kexy Biscuit wrote:
>> On 3/19/2024 1:12 AM, John Paul Adrian Glaubitz wrote:
>>> Hi Hucai,
>>>
>>> On Mon, 2024-03-18 at 22:21 +0800, Huacai Chen wrote:
>>>> Hi, SuperH maintainers,
>>>>
>>>> On Wed, Feb 8, 2023 at 8:59 PM John Paul Adrian Glaubitz
>>>> <[email protected]> wrote:
>>>>>
>>>>> On Thu, 2022-07-14 at 16:41 +0800, Huacai Chen 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
>>>>>> [    3.099465] 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: [email protected]
>>>>>> Signed-off-by: Huacai Chen <[email protected]>
>>>>>> ---
>>>>>>    arch/sh/kernel/cpu/proc.c | 2 +-
>>>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/arch/sh/kernel/cpu/proc.c b/arch/sh/kernel/cpu/proc.c
>>>>>> index a306bcd6b341..5f6d0e827bae 100644
>>>>>> --- a/arch/sh/kernel/cpu/proc.c
>>>>>> +++ b/arch/sh/kernel/cpu/proc.c
>>>>>> @@ -132,7 +132,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
>>>>>>
>>>>>>    static void *c_start(struct seq_file *m, loff_t *pos)
>>>>>>    {
>>>>>> -     return *pos < NR_CPUS ? cpu_data + *pos : NULL;
>>>>>> +     return *pos < nr_cpu_ids ? cpu_data + *pos : NULL;
>>>>>>    }
>>>>>>    static void *c_next(struct seq_file *m, void *v, loff_t *pos)
>>>>>>    {
>>>>>
>>>>> I build-tested the patch and also booted the patched kernel successfully
>>>>> on my SH-7785LCR board.
>>>>>
>>>>> Showing the contents of /proc/cpuinfo works fine, too:
>>>>>
>>>>> root@tirpitz:~> cat /proc/cpuinfo
>>>>> machine         : SH7785LCR
>>>>> processor       : 0
>>>>> cpu family      : sh4a
>>>>> cpu type        : SH7785
>>>>> cut             : 7.x
>>>>> cpu flags       : fpu perfctr llsc
>>>>> cache type      : split (harvard)
>>>>> icache size     : 32KiB (4-way)
>>>>> dcache size     : 32KiB (4-way)
>>>>> address sizes   : 32 bits physical
>>>>> bogomips        : 599.99
>>>>> root@tirpitz:~>
>>>>>
>>>>> Tested-by: John Paul Adrian Glaubitz <[email protected]>
>>>>>
>>>>> I am not sure yet whether the change is also correct as I don't know whether
>>>>> it's possible to change the number of CPUs at runtime on SuperH.
>>>> Can this patch be merged? This is the only one still unmerged in the
>>>> whole series.
>>>
>>> Thanks for the reminder. I will pick it up for 6.10.
>>>
>>> Got sick this week, so I can't pick up anymore patches for 6.9 and will just
>>> send Linus a PR later this week.
>>>
>>> Adrian
>>>
>>
>> Gentle ping on this, can we get this patch merged into 6.12?
> 
> Thanks a lot for the reminder. Since the merge window is about to close, I'll
> pick this up for 6.13 as it hasn't been reviewed yet from what I can see.
> 
> I will definitely pick it up for 6.13 and I'm sorry for the very long delay.
> 
> However, when this patch got posted back then, I wasn't a kernel maintainer yet.
> 
> Adrian
> 

Thank you so much for taking care of this patch, congrats on your new role!

-- 
Best Regards,
Kexy Biscuit