Re: [PATCH] PCI: tegra: Add of_node_put() before return to fix reference leak

[Nishka Dasgupta <nishkadg.linux@gmail.com>]

On 12/08/19 4:35 PM, Lorenzo Pieralisi wrote:
> On Wed, Jul 24, 2019 at 01:54:12PM +0530, Nishka Dasgupta wrote:
>> Each iteration of for_each_child_of_node() puts the previous node, but
>> in the case of a return from the middle of the loop, there is no put,
>> thus causing a reference leak.
>>
>> Hence store these mid-loop return values in variable err and add a new
>> label err_node_put which puts the previous node and returns err. Change
>> six mid-loop return statements to point to this new label instead.
>>
>> Issue found with Coccinelle.
>>
>> Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
>> ---
>> Changes in v2:
> 
> If you are sending a v2 make it explicit in the patch $SUBJECT and send
> the patch --in-reply-to=<message-ID-previous-version> otherwise *I* have
> to fish out of mailing lists previous patches to understand what you are
> doing.

I am very sorry; it won't happen again.

Thanking you,
Nishka
> 
>> - Edit subject line to better reflect changes and match other patches on
>>    this driver.
>> - Edit commit message for readability and accuracy.
>>
>>   drivers/pci/controller/pci-tegra.c | 22 +++++++++++++++-------
>>   1 file changed, 15 insertions(+), 7 deletions(-)
> 
> Applied to pci/tegra, thanks.
> 
> Lorenzo
> 
>> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
>> index 9a917b2456f6..673a1725ef38 100644
>> --- a/drivers/pci/controller/pci-tegra.c
>> +++ b/drivers/pci/controller/pci-tegra.c
>> @@ -2237,14 +2237,15 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
>>   		err = of_pci_get_devfn(port);
>>   		if (err < 0) {
>>   			dev_err(dev, "failed to parse address: %d\n", err);
>> -			return err;
>> +			goto err_node_put;
>>   		}
>>   
>>   		index = PCI_SLOT(err);
>>   
>>   		if (index < 1 || index > soc->num_ports) {
>>   			dev_err(dev, "invalid port number: %d\n", index);
>> -			return -EINVAL;
>> +			err = -EINVAL;
>> +			goto err_node_put;
>>   		}
>>   
>>   		index--;
>> @@ -2253,12 +2254,13 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
>>   		if (err < 0) {
>>   			dev_err(dev, "failed to parse # of lanes: %d\n",
>>   				err);
>> -			return err;
>> +			goto err_node_put;
>>   		}
>>   
>>   		if (value > 16) {
>>   			dev_err(dev, "invalid # of lanes: %u\n", value);
>> -			return -EINVAL;
>> +			err = -EINVAL;
>> +			goto err_node_put;
>>   		}
>>   
>>   		lanes |= value << (index << 3);
>> @@ -2272,13 +2274,15 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
>>   		lane += value;
>>   
>>   		rp = devm_kzalloc(dev, sizeof(*rp), GFP_KERNEL);
>> -		if (!rp)
>> -			return -ENOMEM;
>> +		if (!rp) {
>> +			err = -ENOMEM;
>> +			goto err_node_put;
>> +		}
>>   
>>   		err = of_address_to_resource(port, 0, &rp->regs);
>>   		if (err < 0) {
>>   			dev_err(dev, "failed to parse address: %d\n", err);
>> -			return err;
>> +			goto err_node_put;
>>   		}
>>   
>>   		INIT_LIST_HEAD(&rp->list);
>> @@ -2330,6 +2334,10 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
>>   		return err;
>>   
>>   	return 0;
>> +
>> +err_node_put:
>> +	of_node_put(port);
>> +	return err;
>>   }
>>   
>>   /*
>> -- 
>> 2.19.1
>>