[PATCH 4/6] drivers/pci: introduce missing kfree

[PATCH 4/6] drivers/pci: introduce missing kfree

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

Error handling code following a kmalloc should free the allocated data.
Since the subsequent code that could provoke an error does not use the
allocated data, the allocation is just moved below it.

The semantic match that finds the problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,l;
position p1,p2;
expression *ptr != NULL;
@@

(
if ((x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...)) == NULL) S
|
x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
)
<... when != x
     when != if (...) { <+...x...+> }
x->f = E
...>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
---
 drivers/pci/hotplug/pciehp_acpi.c   |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_acpi.c b/drivers/pci/hotplug/pciehp_acpi.c
index 21734c3..9604801 100644
--- a/drivers/pci/hotplug/pciehp_acpi.c
+++ b/drivers/pci/hotplug/pciehp_acpi.c
@@ -79,14 +79,15 @@ static int __init dummy_probe(struct pcie_device *dev)
 	struct slot *slot, *tmp;
 	struct pci_dev *pdev = dev->port;
 	struct pci_bus *pbus = pdev->subordinate;
-	if (!(slot = kzalloc(sizeof(*slot), GFP_KERNEL)))
-		return -ENOMEM;
 	/* Note: pciehp_detect_mode != PCIEHP_DETECT_ACPI here */
 	if (pciehp_get_hp_hw_control_from_firmware(pdev))
 		return -ENODEV;
 	if (!(pos = pci_find_capability(pdev, PCI_CAP_ID_EXP)))
 		return -ENODEV;
 	pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP, &slot_cap);
+	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
+	if (!slot)
+		return -ENOMEM;
 	slot->number = slot_cap >> 19;
 	list_for_each_entry(tmp, &dummy_slots, slot_list) {
 		if (tmp->number == slot->number)

Re: [PATCH 4/6] drivers/pci: introduce missing kfree

[Matthew Wilcox]

On Sun, Feb 08, 2009 at 10:45:24PM +0100, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> Error handling code following a kmalloc should free the allocated data.
> Since the subsequent code that could provoke an error does not use the
> allocated data, the allocation is just moved below it.
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>

Reviewed-by: Matthew Wilcox <willy@linux.intel.com>

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

Re: [PATCH 4/6] drivers/pci: introduce missing kfree

[Kenji Kaneshige]

Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> Error handling code following a kmalloc should free the allocated data.
> Since the subsequent code that could provoke an error does not use the
> allocated data, the allocation is just moved below it.
> 
> The semantic match that finds the problem is as follows:
> (http://www.emn.fr/x-info/coccinelle/)
> 
> // <smpl>
> @r exists@
> local idexpression x;
> statement S;
> expression E;
> identifier f,l;
> position p1,p2;
> expression *ptr != NULL;
> @@
> 
> (
> if ((x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...)) == NULL) S
> |
> x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
> ...
> if (x == NULL) S
> )
> <... when != x
>      when != if (...) { <+...x...+> }
> x->f = E
> ...>
> (
>  return \(0\|<+...x...+>\|ptr\);
> |
>  return@p2 ...;
> )
> 
> @script:python@
> p1 << r.p1;
> p2 << r.p2;
> @@
> 
> print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>
> ---
>  drivers/pci/hotplug/pciehp_acpi.c   |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/pciehp_acpi.c b/drivers/pci/hotplug/pciehp_acpi.c
> index 21734c3..9604801 100644
> --- a/drivers/pci/hotplug/pciehp_acpi.c
> +++ b/drivers/pci/hotplug/pciehp_acpi.c
> @@ -79,14 +79,15 @@ static int __init dummy_probe(struct pcie_device *dev)
>  	struct slot *slot, *tmp;
>  	struct pci_dev *pdev = dev->port;
>  	struct pci_bus *pbus = pdev->subordinate;
> -	if (!(slot = kzalloc(sizeof(*slot), GFP_KERNEL)))
> -		return -ENOMEM;
>  	/* Note: pciehp_detect_mode != PCIEHP_DETECT_ACPI here */
>  	if (pciehp_get_hp_hw_control_from_firmware(pdev))
>  		return -ENODEV;
>  	if (!(pos = pci_find_capability(pdev, PCI_CAP_ID_EXP)))
>  		return -ENODEV;
>  	pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP, &slot_cap);
> +	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
> +	if (!slot)
> +		return -ENOMEM;
>  	slot->number = slot_cap >> 19;
>  	list_for_each_entry(tmp, &dummy_slots, slot_list) {
>  		if (tmp->number == slot->number)

Thank you for fixing this!

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

Thanks,
Kenji Kaneshige

Re: [PATCH 4/6] drivers/pci: introduce missing kfree

[Jesse Barnes]

On Sunday, February 8, 2009 1:45 pm Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
>
> Error handling code following a kmalloc should free the allocated data.
> Since the subsequent code that could provoke an error does not use the
> allocated data, the allocation is just moved below it.
>
> The semantic match that finds the problem is as follows:
> (http://www.emn.fr/x-info/coccinelle/)

Applied to my linux-next branch, thanks.
-- 
Jesse Barnes, Intel Open Source Technology Center