ACPI/PCI: Fix memory leak fix in pci_acpi_preserve_config

[PATCH] ACPI/PCI: Fix memory leak fix in pci_acpi_preserve_config

Posted by Nirmoy Das 1 month, 1 week ago

The pci_acpi_preserve_config() function is leaking memory by returning
early without freeing the ACPI object on success. Fix that by always
freeing the obj which is not needed by the caller.

Fixes: 9d7d5db8e78e ("PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()")
Signed-off-by: Nirmoy Das <nirmoyd@nvidia.com>
---
 drivers/pci/pci-acpi.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index ddb25960ea47d..9369377725fa0 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -122,6 +122,8 @@ phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
 
 bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
 {
+	bool ret = false;
+
 	if (ACPI_HANDLE(&host_bridge->dev)) {
 		union acpi_object *obj;
 
@@ -135,11 +137,11 @@ bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
 					      1, DSM_PCI_PRESERVE_BOOT_CONFIG,
 					      NULL, ACPI_TYPE_INTEGER);
 		if (obj && obj->integer.value == 0)
-			return true;
+			ret = true;
 		ACPI_FREE(obj);
 	}
 
-	return false;
+	return ret;
 }
 
 /* _HPX PCI Setting Record (Type 0); same as _HPP */
-- 
2.43.0

Re: [PATCH] ACPI/PCI: Fix memory leak fix in pci_acpi_preserve_config

Posted by Bjorn Helgaas 1 month, 1 week ago

On Mon, Aug 25, 2025 at 02:46:42PM -0700, Nirmoy Das wrote:
> The pci_acpi_preserve_config() function is leaking memory by returning
> early without freeing the ACPI object on success. Fix that by always
> freeing the obj which is not needed by the caller.
> 
> Fixes: 9d7d5db8e78e ("PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()")
> Signed-off-by: Nirmoy Das <nirmoyd@nvidia.com>

Applied to pci/misc for v6.18, thanks!

> ---
>  drivers/pci/pci-acpi.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index ddb25960ea47d..9369377725fa0 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -122,6 +122,8 @@ phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
>  
>  bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
>  {
> +	bool ret = false;
> +
>  	if (ACPI_HANDLE(&host_bridge->dev)) {
>  		union acpi_object *obj;
>  
> @@ -135,11 +137,11 @@ bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
>  					      1, DSM_PCI_PRESERVE_BOOT_CONFIG,
>  					      NULL, ACPI_TYPE_INTEGER);
>  		if (obj && obj->integer.value == 0)
> -			return true;
> +			ret = true;
>  		ACPI_FREE(obj);
>  	}
>  
> -	return false;
> +	return ret;
>  }
>  
>  /* _HPX PCI Setting Record (Type 0); same as _HPP */
> -- 
> 2.43.0
>

Re: [PATCH] ACPI/PCI: Fix memory leak fix in pci_acpi_preserve_config

Posted by Nirmoy Das 1 month, 1 week ago

On 26.08.25 00:37, Bjorn Helgaas wrote:
> On Mon, Aug 25, 2025 at 02:46:42PM -0700, Nirmoy Das wrote:
>> The pci_acpi_preserve_config() function is leaking memory by returning
>> early without freeing the ACPI object on success. Fix that by always
>> freeing the obj which is not needed by the caller.
>>
>> Fixes: 9d7d5db8e78e ("PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge()")
>> Signed-off-by: Nirmoy Das <nirmoyd@nvidia.com>
> Applied to pci/misc for v6.18, thanks!
Thanks Bjorn!
>
>> ---
>>   drivers/pci/pci-acpi.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
>> index ddb25960ea47d..9369377725fa0 100644
>> --- a/drivers/pci/pci-acpi.c
>> +++ b/drivers/pci/pci-acpi.c
>> @@ -122,6 +122,8 @@ phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
>>   
>>   bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
>>   {
>> +	bool ret = false;
>> +
>>   	if (ACPI_HANDLE(&host_bridge->dev)) {
>>   		union acpi_object *obj;
>>   
>> @@ -135,11 +137,11 @@ bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
>>   					      1, DSM_PCI_PRESERVE_BOOT_CONFIG,
>>   					      NULL, ACPI_TYPE_INTEGER);
>>   		if (obj && obj->integer.value == 0)
>> -			return true;
>> +			ret = true;
>>   		ACPI_FREE(obj);
>>   	}
>>   
>> -	return false;
>> +	return ret;
>>   }
>>   
>>   /* _HPX PCI Setting Record (Type 0); same as _HPP */
>> -- 
>> 2.43.0
>>