[PATCH v2] powerpc/mpc5xxx: Avoid dereferencing potentially freed memory

Christophe JAILLET
2015-10-15T05:56:20Z

Use 'of_property_read_u32()' instead of 'of_get_property()'+pointer
dereference in order to avoid access to potentially freed memory.

Use 'of_get_next_parent()' to simplify the while() loop and avoid the
need of a temp variable.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
v2: Use of_property_read_u32 instead of of_get_property+pointer dereference
*** Untested ***
---
arch/powerpc/sysdev/mpc5xxx_clocks.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/sysdev/mpc5xxx_clocks.c b/arch/powerpc/sysdev/mpc5xxx_clocks.c
index f4f0301..92fbcf8 100644
--- a/arch/powerpc/sysdev/mpc5xxx_clocks.c
+++ b/arch/powerpc/sysdev/mpc5xxx_clocks.c
@@ -13,21 +13,17 @@

unsigned long mpc5xxx_get_bus_frequency(struct device_node *node)
{
- struct device_node *np;
- const unsigned int *p_bus_freq = NULL;
+ u32 bus_freq = 0;

of_node_get(node);
while (node) {
- p_bus_freq = of_get_property(node, "bus-frequency", NULL);
- if (p_bus_freq)
+ if (!of_property_read_u32(node, "bus-frequency", &bus_freq))
break;

- np = of_get_parent(node);
- of_node_put(node);
- node = np;
+ node = of_get_next_parent(node);
}
of_node_put(node);

- return p_bus_freq ? *p_bus_freq : 0;
+ return bus_freq;
}
EXPORT_SYMBOL(mpc5xxx_get_bus_frequency);
--
2.1.4