dev_opp_list_lock is used everywhere to protect device and OPP lists, but dev_pm_opp_set_sharing_cpus() is missed somehow. And instead we used rcu-lock, which wouldn't help here as we are adding a new list_dev.
This also fixes a problem where we have called kzalloc(..., GFP_KERNEL) from within rcu-lock, which isn't allowed as kzalloc can sleep when called with GFP_KERNEL.
With CONFIG_DEBUG_ATOMIC_SLEEP set, we will see the caller vomiting.
Fixes: 8d4d4e98acd6 ("PM / OPP: Add helpers for initializing CPU OPPs") Reported-by: Michael Turquette mturquette@baylibre.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- Mike: Can you please verify if this fixes it for you..
drivers/base/power/opp/core.c | 2 +- drivers/base/power/opp/cpu.c | 8 ++++---- drivers/base/power/opp/opp.h | 3 +++ 3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c index d5c1149ff123..69f83cbe37b2 100644 --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -27,7 +27,7 @@ */ static LIST_HEAD(dev_opp_list); /* Lock to allow exclusive modification to the device and opp lists */ -static DEFINE_MUTEX(dev_opp_list_lock); +DEFINE_MUTEX(dev_opp_list_lock);
#define opp_rcu_lockdep_assert() \ do { \ diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c index 7654c5606307..91f15b2e25ee 100644 --- a/drivers/base/power/opp/cpu.c +++ b/drivers/base/power/opp/cpu.c @@ -124,12 +124,12 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask) struct device *dev; int cpu, ret = 0;
- rcu_read_lock(); + mutex_lock(&dev_opp_list_lock);
dev_opp = _find_device_opp(cpu_dev); if (IS_ERR(dev_opp)) { ret = -EINVAL; - goto out_rcu_read_unlock; + goto unlock; }
for_each_cpu(cpu, cpumask) { @@ -150,8 +150,8 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask) continue; } } -out_rcu_read_unlock: - rcu_read_unlock(); +unlock: + mutex_unlock(&dev_opp_list_lock);
return 0; } diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h index dcb38f78dae4..7366b2aa8997 100644 --- a/drivers/base/power/opp/opp.h +++ b/drivers/base/power/opp/opp.h @@ -21,6 +21,9 @@ #include <linux/rculist.h> #include <linux/rcupdate.h>
+/* Lock to allow exclusive modification to the device and opp lists */ +extern struct mutex dev_opp_list_lock; + /* * Internal data structure organization with the OPP layer library is as * follows: