Mar 11 2010

drivers/scsi/ses.c: eliminate double free 

Author: Julia Lawall <julia@diku.dk>

The few lines below the kfree of hdr_buf may go to the label err_free
which will also free hdr_buf.  The most straightforward solution seems to
be to just move the kfree of hdr_buf after these gotos.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@r@
identifier E;
expression E1;
iterator I;
statement S;
@@

*kfree(E);
... when != E = E1
    when != I(E,...) S
    when != &E
*kfree(E);
// 

Signed-off-by: Julia Lawall 
Cc: James Bottomley 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 

---
 drivers/scsi/ses.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
 
diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index 1d7a878..0d9d6f7 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -595,8 +595,6 @@ static int ses_intf_add(struct device *cdev,
 		ses_dev->page10_len = len;
 		buf = NULL;
 	}
-	kfree(hdr_buf);
-
 	scomp = kzalloc(sizeof(struct ses_component) * components, GFP_KERNEL);
 	if (!scomp)
 		goto err_free;
@@ -608,6 +606,8 @@ static int ses_intf_add(struct device *cdev,
 		goto err_free;
 	}
 
+	kfree(hdr_buf);
+
 	edev->scratch = ses_dev;
 	for (i = 0; i < components; i++)
 		edev->component[i].scratch = scomp + i;

qlambert