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

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

[Guangshuo Li]

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
---
changelog:
v2:
- Return -ENOMEM directly on allocation failure.

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)
-- 
2.43.0

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

[Christophe JAILLET]

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.

> ---
> 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?

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)

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

[Christophe Leroy]

Le 22/09/2025 à 17:10, Guangshuo Li a écrit :
> [Vous ne recevez pas souvent de courriers de lgs201920130244@gmail.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
> 
> 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
> ---
> changelog:
> v2:
> - Return -ENOMEM directly on allocation failure.
> 
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>

The Signed-off-by: must be above the ---, otherwise it will be lost when 
applying the commit.

With that fixed,

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>



> ---
>   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)
> --
> 2.43.0
> 

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

[Christophe Leroy]

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/

> 
> 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)
> 

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

[Christophe JAILLET]

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)
>>
> 
> 
>