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

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?

-- 
Best Regards,
Kexy Biscuit