[PATCH 7/8] fs/btrfs: introduce missing kfree

From: Julia Lawall
Date: Fri Sep 11 2009 - 12:22:57 EST


From: Julia Lawall <julia@xxxxxxx>

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

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,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)
// </smpl>

Signed-off-by: Julia Lawall <julia@xxxxxxx>
---
fs/btrfs/volumes.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5cf405b..4ced7c3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -446,8 +446,10 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
goto error;

device->name = kstrdup(orig_dev->name, GFP_NOFS);
- if (!device->name)
+ if (!device->name) {
+ kfree(device);
goto error;
+ }

device->devid = orig_dev->devid;
device->work.func = pending_bios_fn;
--
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