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

Rob Herring
2017-03-22T14:56:00Z

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.

> 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