[PATCH 1/2] drivers/watchdog/lantiq_wdt.c: drop iounmap for devm_ allocated data

From: Julia Lawall
Date: Mon Dec 26 2011 - 12:38:42 EST


From: Julia Lawall <julia@xxxxxxx>

Data allocated with devm_ioremap or devm_ioremap_nocache should not be
freed using iounmap, because doing so causes a dangling pointer, and a
subsequent double free.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression x;
@@
(
x = devm_ioremap(...)
|
x = devm_ioremap_nocache(...)
)

@@
expression r.x;
@@
* iounmap(x)
// </smpl>

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

---
drivers/watchdog/lantiq_wdt.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/drivers/watchdog/lantiq_wdt.c b/drivers/watchdog/lantiq_wdt.c
index 102aed0..d3a63be 100644
--- a/drivers/watchdog/lantiq_wdt.c
+++ b/drivers/watchdog/lantiq_wdt.c
@@ -222,9 +222,6 @@ ltq_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&ltq_wdt_miscdev);

- if (ltq_wdt_membase)
- iounmap(ltq_wdt_membase);
-
return 0;
}


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