Jun 01 2010

HID: roccat: introduce missing kfree 

Author: Julia Lawall <julia@diku.dk>

Error handling code following a kmalloc should free the allocated data.

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

// 
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,f1,l;
position p1,p2;
expression *ptr != NULL;
@@

x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...x...+> }
(
x->f1 = E
|
 (x->f1 == NULL || ...)
|
 f(...,x->f1,...)
)
...>
(
 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)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Jiri Kosina 

---
 drivers/hid/hid-roccat.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
 
diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index e05d48e..f6e80c7 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -168,7 +168,7 @@ static int roccat_open(struct inode *inode, struct file *file)
 		printk(KERN_EMERG "roccat device with minor %d doesn't exist\n",
 				minor);
 		error = -ENODEV;
-		goto exit_unlock;
+		goto exit_err;
 	}
 
 	if (!device->open++) {
@@ -178,7 +178,7 @@ static int roccat_open(struct inode *inode, struct file *file)
 					PM_HINT_FULLON);
 			if (error < 0) {
 				--device->open;
-				goto exit_unlock;
+				goto exit_err;
 			}
 		}
 		error = device->hid->ll_driver->open(device->hid);
@@ -187,7 +187,7 @@ static int roccat_open(struct inode *inode, struct file *file)
 				device->hid->ll_driver->power(device->hid,
 						PM_HINT_NORMAL);
 			--device->open;
-			goto exit_unlock;
+			goto exit_err;
 		}
 	}
 
@@ -202,6 +202,9 @@ exit_unlock:
 	mutex_unlock(&device->readers_lock);
 	mutex_unlock(&devices_lock);
 	return error;
+exit_err:
+	kfree(reader);
+	goto exit_unlock;
 }
 
 static int roccat_release(struct inode *inode, struct file *file)

qlambert