[PATCH 3/6] drivers/mfd: Correct use after free

From: Julia Lawall
Date: Tue Dec 22 2009 - 15:31:52 EST


From: Julia Lawall <julia@xxxxxxx>

The structure t7l66xb should not be freed before the subsequent references
to its fields in the arguments to clk_put. Furthermore, this structure is
allocated near the beginning of the function, and a goto to the label
err_noirq appears after a successful allocation, so it would seem that the
kfree should be moved down below this label.

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

// <smpl>
@@
expression x,e;
identifier f;
iterator I;
statement S;
@@

*kfree(x);
... when != &x
when != x = e
when != I(x,...) S
*x->f
// </smpl>

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

---
drivers/mfd/t7l66xb.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mfd/t7l66xb.c b/drivers/mfd/t7l66xb.c
index 2fa0703..dad3768 100644
--- a/drivers/mfd/t7l66xb.c
+++ b/drivers/mfd/t7l66xb.c
@@ -405,12 +405,12 @@ static int t7l66xb_probe(struct platform_device *dev)
err_ioremap:
release_resource(&t7l66xb->rscr);
err_request_scr:
- kfree(t7l66xb);
clk_put(t7l66xb->clk48m);
err_clk48m_get:
clk_put(t7l66xb->clk32k);
err_clk32k_get:
err_noirq:
+ kfree(t7l66xb);
return ret;
}

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