[PATCH 1/1] arm: devtree: fix missing device_node cleanup

[PATCH 1/1] arm: devtree: fix missing device_node cleanup

[Vincenzo Mezzela]

Device node `cpus` is allocated but never released using `of_node_put`.

This patch introduces the __free attribute for `cpus` device_node that
automatically handle the cleanup of the resource by adding a call to
`of_node_put` at the end of the current scope. This enhancement aims to
mitigate memory management issues associated with forgetting to release
the resources.

Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@gmail.com>
---
 arch/arm/kernel/devtree.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index fdb74e64206a..223d66a5fff3 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -70,14 +70,14 @@ void __init arm_dt_init_cpu_maps(void)
 	 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
 	 * read as 0.
 	 */
-	struct device_node *cpu, *cpus;
 	int found_method = 0;
 	u32 i, j, cpuidx = 1;
 	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
 
 	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
 	bool bootcpu_valid = false;
-	cpus = of_find_node_by_path("/cpus");
+	struct device_node *cpu;
+	struct device_node *cpus __free(device_node) = of_find_node_by_path("/cpus");
 
 	if (!cpus)
 		return;
-- 
2.43.0

Re: [PATCH 1/1] arm: devtree: fix missing device_node cleanup

[Javier Carrasco]

On 12/07/2024 11:44, Vincenzo Mezzela wrote:
> Device node `cpus` is allocated but never released using `of_node_put`.
> 
> This patch introduces the __free attribute for `cpus` device_node that
> automatically handle the cleanup of the resource by adding a call to
> `of_node_put` at the end of the current scope. This enhancement aims to
> mitigate memory management issues associated with forgetting to release
> the resources.
> 
> Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@gmail.com>
> ---
>  arch/arm/kernel/devtree.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index fdb74e64206a..223d66a5fff3 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -70,14 +70,14 @@ void __init arm_dt_init_cpu_maps(void)
>  	 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
>  	 * read as 0.
>  	 */
> -	struct device_node *cpu, *cpus;
>  	int found_method = 0;
>  	u32 i, j, cpuidx = 1;
>  	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
>  
>  	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
>  	bool bootcpu_valid = false;
> -	cpus = of_find_node_by_path("/cpus");
> +	struct device_node *cpu;
> +	struct device_node *cpus __free(device_node) = of_find_node_by_path("/cpus");
>  
>  	if (!cpus)
>  		return;

Hello Vincenzo,

If this is a fix, please provide the Fixes: tag as well as Cc: for
stable if it applies.

Best regards,
Javier Carrasco

Re: [PATCH 1/1] arm: devtree: fix missing device_node cleanup

[vincenzo mezzela]

On 7/12/24 11:47, Javier Carrasco wrote:
> On 12/07/2024 11:44, Vincenzo Mezzela wrote:
>> Device node `cpus` is allocated but never released using `of_node_put`.
>>
>> This patch introduces the __free attribute for `cpus` device_node that
>> automatically handle the cleanup of the resource by adding a call to
>> `of_node_put` at the end of the current scope. This enhancement aims to
>> mitigate memory management issues associated with forgetting to release
>> the resources.
>>
>> Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@gmail.com>
>> ---
>>   arch/arm/kernel/devtree.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
>> index fdb74e64206a..223d66a5fff3 100644
>> --- a/arch/arm/kernel/devtree.c
>> +++ b/arch/arm/kernel/devtree.c
>> @@ -70,14 +70,14 @@ void __init arm_dt_init_cpu_maps(void)
>>   	 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
>>   	 * read as 0.
>>   	 */
>> -	struct device_node *cpu, *cpus;
>>   	int found_method = 0;
>>   	u32 i, j, cpuidx = 1;
>>   	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
>>   
>>   	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
>>   	bool bootcpu_valid = false;
>> -	cpus = of_find_node_by_path("/cpus");
>> +	struct device_node *cpu;
>> +	struct device_node *cpus __free(device_node) = of_find_node_by_path("/cpus");
>>   
>>   	if (!cpus)
>>   		return;
> Hello Vincenzo,
>
> If this is a fix, please provide the Fixes: tag as well as Cc: for
> stable if it applies.
>
> Best regards, Javier Carrasco

Sure, will do. :)


Best regards,

Vincenzo


Fixes: a0ae02405076a ("ARM: kernel: add device tree init map function")
Cc: stable@vger.kernel.org