Re: [PATCH v2] powerpc/smp: Add check for kcalloc() failure in parse_thread_groups()

[Christophe JAILLET <christophe.jaillet@wanadoo.fr>]

Le 22/09/2025 à 18:07, Christophe Leroy a écrit :
> 
> 
> Le 22/09/2025 à 17:38, Christophe JAILLET a écrit :
>> Le 22/09/2025 à 17:10, Guangshuo Li a écrit :
>>> As kcalloc() may fail, check its return value to avoid a NULL pointer
>>> dereference when passing it to of_property_read_u32_array().
>>>
>>> Fixes: 790a1662d3a26 ("powerpc/smp: Parse ibm,thread-groups with 
>>> multiple properties")
>>> Cc: stable@vger.kernel.org
>>
>> Signed-off-by that was part of v1, is missing in v2.
> 
> I see it below the ---
> 
>>
>>> ---
>>> changelog:
>>> v2:
>>> - Return -ENOMEM directly on allocation failure.
>>
>> Except for a newline that is removed, v2 is the same as v1, or I miss 
>> something?
> 
> v1 was:
> 
> +       if (!thread_group_array) {
> +               ret = -ENOMEM;
> +               goto out_free;
> +       }
> 
> Which was wrong.
> 
> Well maybe there was several v1, I'm talking about https:// 
> lore.kernel.org/all/20250918131513.3557422-1-lgs201920130244@gmail.com/

Mine, was 
https://lore.kernel.org/lkml/20250922150442.1820675-1-lgs201920130244@gmail.com/

and apparently, there as been 3 v1 : 
https://lore.kernel.org/lkml/?q=powerpc%2Fsmp%3A+Add+check+for+kcalloc%28%29+in+parse_thread_groups%28%29

:/

CJ

> 
>>
>> CJ
>>
>>>
>>> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
>>> ---
>>>   arch/powerpc/kernel/smp.c | 2 ++
>>>   1 file changed, 2 insertions(+)
>>>
>>> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
>>> index 5ac7084eebc0..cfccb9389760 100644
>>> --- a/arch/powerpc/kernel/smp.c
>>> +++ b/arch/powerpc/kernel/smp.c
>>> @@ -822,6 +822,8 @@ static int parse_thread_groups(struct device_node 
>>> *dn,
>>>       count = of_property_count_u32_elems(dn, "ibm,thread-groups");
>>>       thread_group_array = kcalloc(count, sizeof(u32), GFP_KERNEL);
>>> +    if (!thread_group_array)
>>> +        return -ENOMEM;
>>>       ret = of_property_read_u32_array(dn, "ibm,thread-groups",
>>>                        thread_group_array, count);
>>>       if (ret)
>>
> 
> 
>