On 14 April 2013 01:43, Francesco Lavra francescolavra.fl@gmail.com wrote:
for_each_child_of_node(of_find_node_by_path("/cpus"), np) {If of_find_node_by_path() returns NULL, there will be a NULL pointer dereference.
if (count++ != cpu_dev->id)continue;if (!of_get_property(np, "operating-points", NULL))return -ENODATA;cpu_dev->of_node = np;ret = of_init_opp_table(cpu_dev);if (ret)return ret;return 0;of_node_put() should be called on np before returning. Also, the reference count of the parent node should be decremented as well.
These comments apply to the below function dt_get_transition_latency() too.
Thanks Francesco.
Below fixes this (I will send it separately to Rafael):
Subject: [PATCH 1/2] cpufreq: ARM big LITTLE: put DT nodes after using them
DT nodes should be put using of_node_put() to balance their usage counts. This is not done properly in ARM's big LITTLE driver. Fix it.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/cpufreq/arm_big_little_dt.c | 43 +++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 14 deletions(-)
diff --git a/drivers/cpufreq/arm_big_little_dt.c b/drivers/cpufreq/arm_big_little_dt.c index 452ff46..44be311 100644 --- a/drivers/cpufreq/arm_big_little_dt.c +++ b/drivers/cpufreq/arm_big_little_dt.c @@ -31,22 +31,28 @@
static int dt_init_opp_table(struct device *cpu_dev) { - struct device_node *np = NULL; + struct device_node *np, *parent; int count = 0, ret;
- for_each_child_of_node(of_find_node_by_path("/cpus"), np) { + parent = of_find_node_by_path("/cpus"); + if (!parent) { + pr_err("failed to find OF /cpus\n"); + return -ENOENT; + } + + for_each_child_of_node(parent, np) { if (count++ != cpu_dev->id) continue; - if (!of_get_property(np, "operating-points", NULL)) - return -ENODATA; - - cpu_dev->of_node = np; - - ret = of_init_opp_table(cpu_dev); - if (ret) - return ret; - - return 0; + if (!of_get_property(np, "operating-points", NULL)) { + ret = -ENODATA; + } else { + cpu_dev->of_node = np; + ret = of_init_opp_table(cpu_dev); + } + of_node_put(np); + of_node_put(parent); + + return ret; }
return -ENODEV; @@ -54,15 +60,24 @@ static int dt_init_opp_table(struct device *cpu_dev)
static int dt_get_transition_latency(struct device *cpu_dev) { - struct device_node *np = NULL; + struct device_node *np, *parent; u32 transition_latency = CPUFREQ_ETERNAL; int count = 0;
- for_each_child_of_node(of_find_node_by_path("/cpus"), np) { + parent = of_find_node_by_path("/cpus"); + if (!parent) { + pr_err("failed to find OF /cpus\n"); + return -ENOENT; + } + + for_each_child_of_node(parent, np) { if (count++ != cpu_dev->id) continue;
of_property_read_u32(np, "clock-latency", &transition_latency); + of_node_put(np); + of_node_put(parent); + return 0; }