[PATCH 1/2] drivers/scsi: Eliminate double free

From: Julia Lawall
Date: Sun Dec 20 2009 - 12:07:19 EST


From: Julia Lawall <julia@xxxxxxx>

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/)

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

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

Signed-off-by: Julia Lawall <julia@xxxxxxx>

---
drivers/scsi/ses.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index 55b034b..3c8a024 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -591,8 +591,6 @@ 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;
@@ -604,6 +602,8 @@ 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;
--
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