[PATCH 2/2] of/pci: Fix memory leak in of_pci_get_host_bridge_resources

[PATCH 2/2] of/pci: Fix memory leak in of_pci_get_host_bridge_resources

[Jeffy Chen]

Currently we only free the allocated resource struct when error.
This would cause memory leak after pci_free_resource_list.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
---

 drivers/of/of_pci.c | 48 +++++++++++++++---------------------------------
 1 file changed, 15 insertions(+), 33 deletions(-)

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 0ee42c3..269393bc 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -189,9 +189,7 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 			unsigned char busno, unsigned char bus_max,
 			struct list_head *resources, resource_size_t *io_base)
 {
-	struct resource_entry *window;
-	struct resource *res;
-	struct resource *bus_range;
+	struct resource res;
 	struct of_pci_range range;
 	struct of_pci_range_parser parser;
 	char range_type[4];
@@ -200,24 +198,19 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 	if (io_base)
 		*io_base = (resource_size_t)OF_BAD_ADDR;
 
-	bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
-	if (!bus_range)
-		return -ENOMEM;
-
 	pr_info("host bridge %s ranges:\n", dev->full_name);
 
-	err = of_pci_parse_bus_range(dev, bus_range);
+	err = of_pci_parse_bus_range(dev, &res);
 	if (err) {
-		bus_range->start = busno;
-		bus_range->end = bus_max;
-		bus_range->flags = IORESOURCE_BUS;
-		pr_info("  No bus range found for %s, using %pR\n",
-			dev->full_name, bus_range);
+		res.start = busno;
+		res.end = bus_max;
+		res.flags = IORESOURCE_BUS;
+		pr_info("  No bus range found for %s\n", dev->full_name);
 	} else {
-		if (bus_range->end > bus_range->start + bus_max)
-			bus_range->end = bus_range->start + bus_max;
+		if (res.end > res.start + bus_max)
+			res.end = res.start + bus_max;
 	}
-	pci_add_resource(resources, bus_range);
+	pci_add_resource(resources, &res);
 
 	/* Check for ranges property */
 	err = of_pci_range_parser_init(&parser, dev);
@@ -244,24 +237,16 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 		if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
 			continue;
 
-		res = kzalloc(sizeof(struct resource), GFP_KERNEL);
-		if (!res) {
-			err = -ENOMEM;
-			goto parse_failed;
-		}
-
-		err = of_pci_range_to_resource(&range, dev, res);
-		if (err) {
-			kfree(res);
+		err = of_pci_range_to_resource(&range, dev, &res);
+		if (err)
 			continue;
-		}
 
-		if (resource_type(res) == IORESOURCE_IO) {
+		if (resource_type(&res) == IORESOURCE_IO) {
 			if (!io_base) {
 				pr_err("I/O range found for %s. Please provide an io_base pointer to save CPU base address\n",
 					dev->full_name);
 				err = -EINVAL;
-				goto conversion_failed;
+				goto parse_failed;
 			}
 			if (*io_base != (resource_size_t)OF_BAD_ADDR)
 				pr_warn("More than one I/O resource converted for %s. CPU base address for old range lost!\n",
@@ -269,16 +254,13 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 			*io_base = range.cpu_addr;
 		}
 
-		pci_add_resource_offset(resources, res,	res->start - range.pci_addr);
+		pci_add_resource_offset(resources, &res,
+					res.start - range.pci_addr);
 	}
 
 	return 0;
 
-conversion_failed:
-	kfree(res);
 parse_failed:
-	resource_list_for_each_entry(window, resources)
-		kfree(window->res);
 	pci_free_resource_list(resources);
 	return err;
 }
-- 
2.1.4

Re: [PATCH 2/2] of/pci: Fix memory leak in of_pci_get_host_bridge_resources

[Rob Herring]

On Tue, Mar 21, 2017 at 9:25 PM, Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org> wrote:
> Currently we only free the allocated resource struct when error.
> This would cause memory leak after pci_free_resource_list.
>
> Signed-off-by: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
> ---
>
>  drivers/of/of_pci.c | 48 +++++++++++++++---------------------------------
>  1 file changed, 15 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> index 0ee42c3..269393bc 100644
> --- a/drivers/of/of_pci.c
> +++ b/drivers/of/of_pci.c
> @@ -189,9 +189,7 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
>                         unsigned char busno, unsigned char bus_max,
>                         struct list_head *resources, resource_size_t *io_base)
>  {
> -       struct resource_entry *window;
> -       struct resource *res;
> -       struct resource *bus_range;
> +       struct resource res;
>         struct of_pci_range range;
>         struct of_pci_range_parser parser;
>         char range_type[4];
> @@ -200,24 +198,19 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
>         if (io_base)
>                 *io_base = (resource_size_t)OF_BAD_ADDR;
>
> -       bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
> -       if (!bus_range)
> -               return -ENOMEM;
> -
>         pr_info("host bridge %s ranges:\n", dev->full_name);
>
> -       err = of_pci_parse_bus_range(dev, bus_range);
> +       err = of_pci_parse_bus_range(dev, &res);
>         if (err) {
> -               bus_range->start = busno;
> -               bus_range->end = bus_max;
> -               bus_range->flags = IORESOURCE_BUS;
> -               pr_info("  No bus range found for %s, using %pR\n",
> -                       dev->full_name, bus_range);
> +               res.start = busno;
> +               res.end = bus_max;
> +               res.flags = IORESOURCE_BUS;
> +               pr_info("  No bus range found for %s\n", dev->full_name);
>         } else {
> -               if (bus_range->end > bus_range->start + bus_max)
> -                       bus_range->end = bus_range->start + bus_max;
> +               if (res.end > res.start + bus_max)
> +                       res.end = res.start + bus_max;
>         }
> -       pci_add_resource(resources, bus_range);
> +       pci_add_resource(resources, &res);

You are passing a stack variable to pci_add_resource and it doesn't
make a copy of it. I assume the resource needs to live after you exit
this function.

If we have a leak, can't you just add a free in the correct spot? That
would be a lot easier to review.

Rob
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Re: [PATCH 2/2] of/pci: Fix memory leak in of_pci_get_host_bridge_resources

[Rob Herring]

On Wed, Mar 22, 2017 at 9:39 AM, Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> On Tue, Mar 21, 2017 at 9:25 PM, Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org> wrote:
>> Currently we only free the allocated resource struct when error.
>> This would cause memory leak after pci_free_resource_list.
>>
>> Signed-off-by: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
>> ---
>>
>>  drivers/of/of_pci.c | 48 +++++++++++++++---------------------------------
>>  1 file changed, 15 insertions(+), 33 deletions(-)
>>
>> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
>> index 0ee42c3..269393bc 100644
>> --- a/drivers/of/of_pci.c
>> +++ b/drivers/of/of_pci.c
>> @@ -189,9 +189,7 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
>>                         unsigned char busno, unsigned char bus_max,
>>                         struct list_head *resources, resource_size_t *io_base)
>>  {
>> -       struct resource_entry *window;
>> -       struct resource *res;
>> -       struct resource *bus_range;
>> +       struct resource res;
>>         struct of_pci_range range;
>>         struct of_pci_range_parser parser;
>>         char range_type[4];
>> @@ -200,24 +198,19 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
>>         if (io_base)
>>                 *io_base = (resource_size_t)OF_BAD_ADDR;
>>
>> -       bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
>> -       if (!bus_range)
>> -               return -ENOMEM;
>> -
>>         pr_info("host bridge %s ranges:\n", dev->full_name);
>>
>> -       err = of_pci_parse_bus_range(dev, bus_range);
>> +       err = of_pci_parse_bus_range(dev, &res);
>>         if (err) {
>> -               bus_range->start = busno;
>> -               bus_range->end = bus_max;
>> -               bus_range->flags = IORESOURCE_BUS;
>> -               pr_info("  No bus range found for %s, using %pR\n",
>> -                       dev->full_name, bus_range);
>> +               res.start = busno;
>> +               res.end = bus_max;
>> +               res.flags = IORESOURCE_BUS;
>> +               pr_info("  No bus range found for %s\n", dev->full_name);
>>         } else {
>> -               if (bus_range->end > bus_range->start + bus_max)
>> -                       bus_range->end = bus_range->start + bus_max;
>> +               if (res.end > res.start + bus_max)
>> +                       res.end = res.start + bus_max;
>>         }
>> -       pci_add_resource(resources, bus_range);
>> +       pci_add_resource(resources, &res);
>
> You are passing a stack variable to pci_add_resource and it doesn't
> make a copy of it. I assume the resource needs to live after you exit
> this function.

Ah, found your 1st patch changing the behavior. I'm surprised that
change works without affecting anyone else.

> If we have a leak, can't you just add a free in the correct spot? That
> would be a lot easier to review.
>
> Rob
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Re: [PATCH 2/2] of/pci: Fix memory leak in of_pci_get_host_bridge_resources

[jeffy]

Hi Rob,

On 03/22/2017 10:55 PM, Rob Herring wrote:
> On Wed, Mar 22, 2017 at 9:39 AM, Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>> On Tue, Mar 21, 2017 at 9:25 PM, Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org> wrote:
>>> Currently we only free the allocated resource struct when error.
>>> This would cause memory leak after pci_free_resource_list.
>>>
>>> Signed-off-by: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
>>> ---
>>>
>>>   drivers/of/of_pci.c | 48 +++++++++++++++---------------------------------
>>>   1 file changed, 15 insertions(+), 33 deletions(-)
>>>
>>> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
>>> index 0ee42c3..269393bc 100644
>>> --- a/drivers/of/of_pci.c
>>> +++ b/drivers/of/of_pci.c
>>> @@ -189,9 +189,7 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
>>>                          unsigned char busno, unsigned char bus_max,
>>>                          struct list_head *resources, resource_size_t *io_base)
>>>   {
>>> -       struct resource_entry *window;
>>> -       struct resource *res;
>>> -       struct resource *bus_range;
>>> +       struct resource res;
>>>          struct of_pci_range range;
>>>          struct of_pci_range_parser parser;
>>>          char range_type[4];
>>> @@ -200,24 +198,19 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
>>>          if (io_base)
>>>                  *io_base = (resource_size_t)OF_BAD_ADDR;
>>>
>>> -       bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
>>> -       if (!bus_range)
>>> -               return -ENOMEM;
>>> -
>>>          pr_info("host bridge %s ranges:\n", dev->full_name);
>>>
>>> -       err = of_pci_parse_bus_range(dev, bus_range);
>>> +       err = of_pci_parse_bus_range(dev, &res);
>>>          if (err) {
>>> -               bus_range->start = busno;
>>> -               bus_range->end = bus_max;
>>> -               bus_range->flags = IORESOURCE_BUS;
>>> -               pr_info("  No bus range found for %s, using %pR\n",
>>> -                       dev->full_name, bus_range);
>>> +               res.start = busno;
>>> +               res.end = bus_max;
>>> +               res.flags = IORESOURCE_BUS;
>>> +               pr_info("  No bus range found for %s\n", dev->full_name);
>>>          } else {
>>> -               if (bus_range->end > bus_range->start + bus_max)
>>> -                       bus_range->end = bus_range->start + bus_max;
>>> +               if (res.end > res.start + bus_max)
>>> +                       res.end = res.start + bus_max;
>>>          }
>>> -       pci_add_resource(resources, bus_range);
>>> +       pci_add_resource(resources, &res);
>>
>> You are passing a stack variable to pci_add_resource and it doesn't
>> make a copy of it. I assume the resource needs to live after you exit
>> this function.
>
> Ah, found your 1st patch changing the behavior. I'm surprised that
> change works without affecting anyone else.
sorry, i should add a cover-letter first. and you're right, that would 
affect others(for example the ioport_resource/iomem_resource).
>
>> If we have a leak, can't you just add a free in the correct spot? That
>> would be a lot easier to review.
it seems hard to tell which resources in the list need to be freed after 
all...
>>
>> Rob
>
>
>


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