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

jeffy
2017-03-23T08:23:07Z

Hi Rob,

On 03/22/2017 10:55 PM, Rob Herring wrote:
> On Wed, Mar 22, 2017 at 9:39 AM, Rob Herring <robh@kernel.org> wrote:
>> On Tue, Mar 21, 2017 at 9:25 PM, Jeffy Chen <jeffy.chen@rock-chips.com> 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@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);
>>
>> 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
>
>
>