| Message ID | 1578383599-11207-1-git-send-email-qiwuchen55@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | viresh kumar |
| Headers | show |
| Series | [v3] cpufreq: s3c: fix unbalances of cpufreq policy refcount | expand |
On 07-01-20, 15:53, qiwuchen55@gmail.com wrote: > From: chenqiwu <chenqiwu@xiaomi.com> > > The cpufreq_reboot_notifier_evt() call cpufreq_cpu_get() to get the > cpufreq policy of cpu0, meanwhile, it also increments the kobject > reference count to mark it busy. However, a corresponding call of > cpufreq_cpu_put() is ignored to decrement the kobject reference count > back, which may lead to a potential stuck risk that the cpuhp thread > deadly waits for dropping of kobject refcount when cpufreq policy free. > > With this patch, the cpuhp thread can be easily exercised by attempting > to force an unbind of the CPUfreq driver. > > Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> > --- > changes in v3: > - Rewrite title and commit message. > --- > drivers/cpufreq/s3c2416-cpufreq.c | 12 +++++++++++- > drivers/cpufreq/s5pv210-cpufreq.c | 11 ++++++++++- > 2 files changed, 21 insertions(+), 2 deletions(-) Applied. Thanks.
On 19-01-20, 10:25, qiwu chen wrote: > Hi > Any progress about this patch? I already applied it in my tree, it will be part for v5.5-rc1.
On Mon, Jan 20, 2020 at 10:58:21AM +0530, Viresh Kumar wrote: > On 19-01-20, 10:25, qiwu chen wrote: > > Hi > > Any progress about this patch? > > I already applied it in my tree, it will be part for v5.5-rc1. > > -- > viresh OK, Thanks a lot! Qiwu
diff --git a/drivers/cpufreq/s3c2416-cpufreq.c b/drivers/cpufreq/s3c2416-cpufreq.c index 1069103..5c221bc 100644 --- a/drivers/cpufreq/s3c2416-cpufreq.c +++ b/drivers/cpufreq/s3c2416-cpufreq.c @@ -304,6 +304,7 @@ static int s3c2416_cpufreq_reboot_notifier_evt(struct notifier_block *this, { struct s3c2416_data *s3c_freq = &s3c2416_cpufreq; int ret; + struct cpufreq_policy *policy; mutex_lock(&cpufreq_lock); @@ -318,7 +319,16 @@ static int s3c2416_cpufreq_reboot_notifier_evt(struct notifier_block *this, */ if (s3c_freq->is_dvs) { pr_debug("cpufreq: leave dvs on reboot\n"); - ret = cpufreq_driver_target(cpufreq_cpu_get(0), FREQ_SLEEP, 0); + + policy = cpufreq_cpu_get(0); + if (!policy) { + pr_debug("cpufreq: get no policy for cpu0\n"); + return NOTIFY_BAD; + } + + ret = cpufreq_driver_target(policy, FREQ_SLEEP, 0); + cpufreq_cpu_put(policy); + if (ret < 0) return NOTIFY_BAD; } diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c index 5d10030..e84281e 100644 --- a/drivers/cpufreq/s5pv210-cpufreq.c +++ b/drivers/cpufreq/s5pv210-cpufreq.c @@ -555,8 +555,17 @@ static int s5pv210_cpufreq_reboot_notifier_event(struct notifier_block *this, unsigned long event, void *ptr) { int ret; + struct cpufreq_policy *policy; + + policy = cpufreq_cpu_get(0); + if (!policy) { + pr_debug("cpufreq: get no policy for cpu0\n"); + return NOTIFY_BAD; + } + + ret = cpufreq_driver_target(policy, SLEEP_FREQ, 0); + cpufreq_cpu_put(policy); - ret = cpufreq_driver_target(cpufreq_cpu_get(0), SLEEP_FREQ, 0); if (ret < 0) return NOTIFY_BAD;