Re: [PATCH] drivers/base/node: Handle error properly in register_one_node()

[Donet Tom <donettom@linux.ibm.com>]

On 7/4/25 5:59 PM, David Hildenbrand wrote:
> On 02.07.25 14:59, Donet Tom wrote:
>>
>> On 7/2/25 6:16 PM, Oscar Salvador wrote:
>>> On Wed, Jul 02, 2025 at 06:28:56AM -0500, Donet Tom wrote:
>>>> If register_node() returns an error, it is not handled correctly.
>>>> The function will proceed further and try to register CPUs under the
>>>> node, which is not correct.
>>>>
>>>> So, in this patch, if register_node() returns an error, we return
>>>> immediately from the function.
>>>>
>>>> Signed-off-by: Donet Tom <donettom@linux.ibm.com>
>>>> ---
>>>>
>>> ...
>>>> diff --git a/drivers/base/node.c b/drivers/base/node.c
>>>> index bef84f01712f..aec991b4c0b2 100644
>>>> --- a/drivers/base/node.c
>>>> +++ b/drivers/base/node.c
>>>> @@ -885,6 +885,8 @@ int register_one_node(int nid)
>>>>        node_devices[nid] = node;
>>>>           error = register_node(node_devices[nid], nid);
>>>> +    if (error)
>>>> +        return error;
>>> Ok, all current callers (based on mm-unstable) panic or BUG() if 
>>> this fails,
>>> but powerpc, in init_phb_dynamic(), which keeps on going.
>>> Unless it panics somewhere down the road as well.
>>>
>>> So I think we need to:
>>>
>>>    node_devices[nid] = NULL
>>>    kfree(node)
>>>
>>>    ?
>>
>>
>> Yes, I will add this too.
>>
>> But one question: if register_node() fails, is it okay to continue, or
>> should we panic?
>>
>> What is the correct way to handle this?
>
> panic() or BUG() is not the answer :)
>
> Try to recover ...

Got it, thank you very much, David.