kernel.git/drivers/cpufreq/cpufreq.c, branch linux-5.0.y

sched/cpufreq: Fix kobject memleak

2019-05-31T13:44:56Z

[ Upstream commit 9a4f26cc98d81b67ecc23b890c28e2df324e29f3 ] Currently the error return path from kobject_init_and_add() is not followed by a call to kobject_put() - which means we are leaking the kobject. Fix it by adding a call to kobject_put() in the error path of kobject_init_and_add(). Signed-off-by: Tobin C. Harding Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Thomas Gleixner Cc: Tobin C. Harding Cc: Vincent Guittot Cc: Viresh Kumar Link: http://lkml.kernel.org/r/20190430001144.24890-1-tobin@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

cpufreq: Use struct kobj_attribute instead of struct global_attr

2019-03-10T06:08:57Z

commit 625c85a62cb7d3c79f6e16de3cfa972033658250 upstream. The cpufreq_global_kobject is created using kobject_create_and_add() helper, which assigns the kobj_type as dynamic_kobj_ktype and show/store routines are set to kobj_attr_show() and kobj_attr_store(). These routines pass struct kobj_attribute as an argument to the show/store callbacks. But all the cpufreq files created using the cpufreq_global_kobject expect the argument to be of type struct attribute. Things work fine currently as no one accesses the "attr" argument. We may not see issues even if the argument is used, as struct kobj_attribute has struct attribute as its first element and so they will both get same address. But this is logically incorrect and we should rather use struct kobj_attribute instead of struct global_attr in the cpufreq core and drivers and the show/store callbacks should take struct kobj_attribute as argument instead. This bug is caught using CFI CLANG builds in android kernel which catches mismatch in function prototypes for such callbacks. Reported-by: Donghee Han Reported-by: Sangkyu Kim Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

Merge branches 'pm-cpuidle', 'pm-cpufreq' and 'pm-sleep'

2019-01-11T09:09:51Z

* pm-cpuidle: doc: trace: fix reference to cpuidle documentation file cpuidle / Documentation: Update cpuidle MAINTAINERS entry * pm-cpufreq: cpufreq: scmi: Fix frequency invariance in slow path cpufreq: check if policy is inactive early in __cpufreq_get() cpufreq: scpi/scmi: Fix freeing of dynamic OPPs cpufreq / Documentation: Update cpufreq MAINTAINERS entry * pm-sleep: PM: sleep: call devfreq suspend/resume

cpufreq: check if policy is inactive early in __cpufreq_get()

2019-01-08T09:49:50Z

cpuinfo_cur_freq gets current CPU frequency as detected by hardware while scaling_cur_freq last known CPU frequency. Some platforms may not allow checking the CPU frequency of an offline CPU or the associated resources may have been released via cpufreq_exit when the CPU gets offlined, in which case the policy would have been invalidated already. If we attempt to get current frequency from the hardware, it may result in hang or crash. For example on Juno, I see: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188 [0000000000000188] pgd=0000000000000000 Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: CPU: 5 PID: 4202 Comm: cat Not tainted 4.20.0-08251-ga0f2c0318a15-dirty #87 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform pstate: 40000005 (nZcv daif -PAN -UAO) pc : scmi_cpufreq_get_rate+0x34/0xb0 lr : scmi_cpufreq_get_rate+0x34/0xb0 Call trace: scmi_cpufreq_get_rate+0x34/0xb0 __cpufreq_get+0x34/0xc0 show_cpuinfo_cur_freq+0x24/0x78 show+0x40/0x60 sysfs_kf_seq_show+0xc0/0x148 kernfs_seq_show+0x44/0x50 seq_read+0xd4/0x480 kernfs_fop_read+0x15c/0x208 __vfs_read+0x60/0x188 vfs_read+0x94/0x150 ksys_read+0x6c/0xd8 __arm64_sys_read+0x24/0x30 el0_svc_common+0x78/0x100 el0_svc_handler+0x38/0x78 el0_svc+0x8/0xc ---[ end trace 3d1024e58f77f6b2 ]--- So fix the issue by checking if the policy is invalid early in __cpufreq_get before attempting to get the current frequency. Signed-off-by: Sudeep Holla Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

sched/topology: Make Energy Aware Scheduling depend on schedutil

2018-12-11T14:17:00Z

Energy Aware Scheduling (EAS) is designed with the assumption that frequencies of CPUs follow their utilization value. When using a CPUFreq governor other than schedutil, the chances of this assumption being true are small, if any. When schedutil is being used, EAS' predictions are at least consistent with the frequency requests. Although those requests have no guarantees to be honored by the hardware, they should at least guide DVFS in the right direction and provide some hope in regards to the EAS model being accurate. To make sure EAS is only used in a sane configuration, create a strong dependency on schedutil being used. Since having sugov compiled-in does not provide that guarantee, make CPUFreq call a scheduler function on governor changes hence letting it rebuild the scheduling domains, check the governors of the online CPUs, and enable/disable EAS accordingly. Signed-off-by: Quentin Perret Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Thomas Gleixner Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-9-quentin.perret@arm.com Signed-off-by: Ingo Molnar

cpufreq: remove unnecessary unlikely()

2018-09-10T10:04:42Z

WARN_ON() already contains an unlikely(), so it's not necessary to wrap it into another. Signed-off-by: Igor Stoppa Signed-off-by: Rafael J. Wysocki

cpufreq: Fix a circular lock dependency problem

2018-07-26T08:37:36Z

With lockdep turned on, the following circular lock dependency problem was reported: [ 57.470040] ====================================================== [ 57.502900] WARNING: possible circular locking dependency detected [ 57.535208] 4.18.0-0.rc3.1.el8+7.x86_64+debug #1 Tainted: G [ 57.577761] ------------------------------------------------------ [ 57.609714] tuned/1505 is trying to acquire lock: [ 57.633808] 00000000559deec5 (cpu_hotplug_lock.rw_sem){++++}, at: store+0x27/0x120 [ 57.672880] [ 57.672880] but task is already holding lock: [ 57.702184] 000000002136ca64 (kn->count#118){++++}, at: kernfs_fop_write+0x1d0/0x410 [ 57.742176] [ 57.742176] which lock already depends on the new lock. [ 57.742176] [ 57.785220] [ 57.785220] the existing dependency chain (in reverse order) is: : [ 58.932512] other info that might help us debug this: [ 58.932512] [ 58.973344] Chain exists of: [ 58.973344] cpu_hotplug_lock.rw_sem --> subsys mutex#5 --> kn->count#118 [ 58.973344] [ 59.030795] Possible unsafe locking scenario: [ 59.030795] [ 59.061248] CPU0 CPU1 [ 59.085377] ---- ---- [ 59.108160] lock(kn->count#118); [ 59.124935] lock(subsys mutex#5); [ 59.156330] lock(kn->count#118); [ 59.186088] lock(cpu_hotplug_lock.rw_sem); [ 59.208541] [ 59.208541] *** DEADLOCK *** In the cpufreq_register_driver() function, the lock sequence is: cpus_read_lock --> kn->count For the cpufreq sysfs store method, the lock sequence is: kn->count --> cpus_read_lock These sequences are actually safe as they are taking a share lock on cpu_hotplug_lock. However, the current lockdep code doesn't check for share locking when detecting circular lock dependency. Fixing that could be a substantial effort. Instead, we can work around this problem by using cpus_read_trylock() in the store method which is much simpler. The chance of not getting the read lock is very small. If that happens, the userspace application that writes the sysfs file will get an error. Signed-off-by: Waiman Long Signed-off-by: Rafael J. Wysocki

cpufreq: trace frequency limits change

2018-07-26T08:17:47Z

systrace used for tracing for Android systems has carried a patch for many years in the Android tree that traces when the cpufreq limits change. With the help of this information, systrace can know when the policy limits change and can visually display the data. Lets add upstream support for the same. Signed-off-by: Ruchi Kandoi Signed-off-by: Joel Fernandes (Google) Acked-by: Viresh Kumar Acked-by: Steven Rostedt (VMware) Signed-off-by: Rafael J. Wysocki

cpufreq: Use static SRCU initializer

2018-05-30T09:16:59Z

Use the static SRCU initializer for `cpufreq_transition_notifier_list'. This avoids the init_cpufreq_transition_notifier_list() initcall. Its only purpose is to initialize the SRCU notifier once during boot and set another variable which is used as an indicator whether the init was perfromed before cpufreq_register_notifier() was used. Signed-off-by: Sebastian Andrzej Siewior Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Fix new policy initialization during limits updates via sysfs

2018-05-30T08:11:34Z

If the policy limits are updated via cpufreq_update_policy() and subsequently via sysfs, the limits stored in user_policy may be set incorrectly. For example, if both min and max are set via sysfs to the maximum available frequency, user_policy.min and user_policy.max will also be the maximum. If a policy notifier triggered by cpufreq_update_policy() lowers both the min and the max at this point, that change is not reflected by the user_policy limits, so if the max is updated again via sysfs to the same lower value, then user_policy.max will be lower than user_policy.min which shouldn't happen. In particular, if one of the policy CPUs is then taken offline and back online, cpufreq_set_policy() will fail for it due to a failing limits check. To prevent that from happening, initialize the min and max fields of the new_policy object to the ones stored in user_policy that were previously set via sysfs. Signed-off-by: Kevin Wangtao Acked-by: Viresh Kumar [ rjw: Subject & changelog ] Cc: All applicable Signed-off-by: Rafael J. Wysocki