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

[David Hildenbrand <david@redhat.com>]

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 ...

-- 
Cheers,

David / dhildenb