cpufreq: Fix timer/workqueue corruption due to double queueing

PATCH In review Stephen Boyd 3 participants 10 messages Aug 26, 2013 – Aug 29, 2013 CPU frequency scaling framework

Share & tools

Stephen Boyd

author

2013-08-26 22:45 UTC #0 lore raw

PATCH 1/1 cpufreq: Fix timer/workqueue corruption due to double queueing

When a CPU is hot removed we'll cancel all the delayed work items via gov_cancel_work(). Normally this will just cancel a delayed timer on each CPU that the policy is managing and the work won't run, but if the work is already running the workqueue code will wait for the work to finish before continuing to prevent the work items from re-queuing themselves like they normally do. This scheme will work most of the time, except for the case where the work function determines that it should adjust the delay for all other CPUs that the policy is managing. If this scenario occurs, the canceling CPU will cancel its own work but queue up the other CPUs works to run. For example:

CPU0 CPU1
---- ----
cpu_down()
...
__cpufreq_remove_dev()
cpufreq_governor_dbs()
case CPUFREQ_GOV_STOP:
gov_cancel_work(dbs_data, policy);
cpu0 work is canceled
timer is canceled
cpu1 work is canceled <work runs>
<waits for cpu1> od_dbs_timer()
gov_queue_work(*, *, true);
cpu0 work queued cpu1 work queued cpu2 work queued
...
cpu1 work is canceled
cpu2 work is canceled
...

At the end of the GOV_STOP case cpu0 still has a work queued to run although the code is expecting all of the works to be canceled. __cpufreq_remove_dev() will then proceed to re-initialize all the other CPUs works except for the CPU that is going down. The CPUFREQ_GOV_START case in cpufreq_governor_dbs() will trample over the queued work and debugobjects will spit out a warning:

WARNING: at lib/debugobjects.c:260 debug_print_object+0x94/0xbc()
ODEBUG: init active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x10
Modules linked in:
CPU: 0 PID: 1491 Comm: sh Tainted: G        W    3.10.0 #19
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c01904cc>] (warn_slowpath_common+0x4c/0x6c)
[<c01904cc>] (warn_slowpath_common+0x4c/0x6c) from [<c019056c>] (warn_slowpath_fmt+0x2c/0x3c)
[<c019056c>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0388a7c>] (debug_print_object+0x94/0xbc)
[<c0388a7c>] (debug_print_object+0x94/0xbc) from [<c0388e34>] (__debug_object_init+0x2d0/0x340)
[<c0388e34>] (__debug_object_init+0x2d0/0x340) from [<c019e3b0>] (init_timer_key+0x14/0xb0)
[<c019e3b0>] (init_timer_key+0x14/0xb0) from [<c0635f78>] (cpufreq_governor_dbs+0x3e8/0x5f8)
[<c0635f78>] (cpufreq_governor_dbs+0x3e8/0x5f8) from [<c06325a0>] (__cpufreq_governor+0xdc/0x1a4)
[<c06325a0>] (__cpufreq_governor+0xdc/0x1a4) from [<c0633704>] (__cpufreq_remove_dev.isra.10+0x3b4/0x434)
[<c0633704>] (__cpufreq_remove_dev.isra.10+0x3b4/0x434) from [<c08989f4>] (cpufreq_cpu_callback+0x60/0x80)
[<c08989f4>] (cpufreq_cpu_callback+0x60/0x80) from [<c08a43c0>] (notifier_call_chain+0x38/0x68)
[<c08a43c0>] (notifier_call_chain+0x38/0x68) from [<c01938e0>] (__cpu_notify+0x28/0x40)
[<c01938e0>] (__cpu_notify+0x28/0x40) from [<c0892ad4>] (_cpu_down+0x7c/0x2c0)
[<c0892ad4>] (_cpu_down+0x7c/0x2c0) from [<c0892d3c>] (cpu_down+0x24/0x40)
[<c0892d3c>] (cpu_down+0x24/0x40) from [<c0893ea8>] (store_online+0x2c/0x74)
[<c0893ea8>] (store_online+0x2c/0x74) from [<c04519d8>] (dev_attr_store+0x18/0x24)
[<c04519d8>] (dev_attr_store+0x18/0x24) from [<c02a69d4>] (sysfs_write_file+0x100/0x148)
[<c02a69d4>] (sysfs_write_file+0x100/0x148) from [<c0255c18>] (vfs_write+0xcc/0x174)
[<c0255c18>] (vfs_write+0xcc/0x174) from [<c0255f70>] (SyS_write+0x38/0x64)
[<c0255f70>] (SyS_write+0x38/0x64) from [<c0106120>] (ret_fast_syscall+0x0/0x30)

The simplest fix is to check and see if the governor is being stopped and ignore the all_cpus flag so that only the work that's being canceled has the chance to re-queue itself.

Signed-off-by Stephen Boyd <[email protected]>

---

This should probably go to stable. I think this all started happening in commit 031299b3be30f3ec (cpufreq: governors: Avoid unnecessary per cpu timer interrupts, 2013-02-27).

 drivers/cpufreq/cpufreq_governor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/cpufreq/cpufreq_governor.c +1 -1

index 7b839a8..0375a3c 100644
@@ -133,7 +133,7 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 {
 	int i;
 
-	if (!all_cpus) {
+	if (!all_cpus || !policy->governor_enabled) {
 		__gov_queue_work(smp_processor_id(), dbs_data, delay);
 	} else {
 		for_each_cpu(i, policy->cpus)

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Viresh Kumar

maintainer

2013-08-27 06:31 UTC #1 lore raw

drivers/cpufreq/cpufreq_governor.c void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, · line 139

Quoted 10 lines · Stephen Boyd

+++ b/drivers/cpufreq/cpufreq_governor.c

drivers/cpufreq/cpufreq_governor.c +1 -1

@@ -133,7 +133,7 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 {
        int i;
 
-       if (!all_cpus) {
+       if (!all_cpus || !policy->governor_enabled) {
                __gov_queue_work(smp_processor_id(), dbs_data, delay);
        } else {
                for_each_cpu(i, policy->cpus)

Shouldn't we simply do this instead at the top of this function?

Quoted 2 lines

(quoted diff) +2 -0

+       if (!policy->governor_enabled)
+              return;

Stephen Boyd

author

2013-08-27 18:47 UTC #2 lore raw

PATCH 1/1 cpufreq: Fix timer/workqueue corruption due to double queueing

WARNING: at lib/debugobjects.c:260 debug_print_object+0x94/0xbc()
ODEBUG: init active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x10
Modules linked in:
CPU: 0 PID: 1491 Comm: sh Tainted: G        W    3.10.0 #19
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c01904cc>] (warn_slowpath_common+0x4c/0x6c)
[<c01904cc>] (warn_slowpath_common+0x4c/0x6c) from [<c019056c>] (warn_slowpath_fmt+0x2c/0x3c)
[<c019056c>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0388a7c>] (debug_print_object+0x94/0xbc)
[<c0388a7c>] (debug_print_object+0x94/0xbc) from [<c0388e34>] (__debug_object_init+0x2d0/0x340)
[<c0388e34>] (__debug_object_init+0x2d0/0x340) from [<c019e3b0>] (init_timer_key+0x14/0xb0)
[<c019e3b0>] (init_timer_key+0x14/0xb0) from [<c0635f78>] (cpufreq_governor_dbs+0x3e8/0x5f8)
[<c0635f78>] (cpufreq_governor_dbs+0x3e8/0x5f8) from [<c06325a0>] (__cpufreq_governor+0xdc/0x1a4)
[<c06325a0>] (__cpufreq_governor+0xdc/0x1a4) from [<c0633704>] (__cpufreq_remove_dev.isra.10+0x3b4/0x434)
[<c0633704>] (__cpufreq_remove_dev.isra.10+0x3b4/0x434) from [<c08989f4>] (cpufreq_cpu_callback+0x60/0x80)
[<c08989f4>] (cpufreq_cpu_callback+0x60/0x80) from [<c08a43c0>] (notifier_call_chain+0x38/0x68)
[<c08a43c0>] (notifier_call_chain+0x38/0x68) from [<c01938e0>] (__cpu_notify+0x28/0x40)
[<c01938e0>] (__cpu_notify+0x28/0x40) from [<c0892ad4>] (_cpu_down+0x7c/0x2c0)
[<c0892ad4>] (_cpu_down+0x7c/0x2c0) from [<c0892d3c>] (cpu_down+0x24/0x40)
[<c0892d3c>] (cpu_down+0x24/0x40) from [<c0893ea8>] (store_online+0x2c/0x74)
[<c0893ea8>] (store_online+0x2c/0x74) from [<c04519d8>] (dev_attr_store+0x18/0x24)
[<c04519d8>] (dev_attr_store+0x18/0x24) from [<c02a69d4>] (sysfs_write_file+0x100/0x148)
[<c02a69d4>] (sysfs_write_file+0x100/0x148) from [<c0255c18>] (vfs_write+0xcc/0x174)
[<c0255c18>] (vfs_write+0xcc/0x174) from [<c0255f70>] (SyS_write+0x38/0x64)
[<c0255f70>] (SyS_write+0x38/0x64) from [<c0106120>] (ret_fast_syscall+0x0/0x30)

Signed-off-by Stephen Boyd <[email protected]>

---

Quoted 6 lines · Viresh Kumar

Quoted 5 lines · Stephen Boyd
+++ b/drivers/cpufreq/cpufreq_governor.c
(quoted diff) +0 -0
@@ -133,7 +133,7 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 {
        int i;
 

Quoted 10 lines

Review void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, · line 139
Quoted 5 lines
(quoted diff) +1 -1
-       if (!all_cpus) {
+       if (!all_cpus || !policy->governor_enabled) {
                __gov_queue_work(smp_processor_id(), dbs_data, delay);
        } else {
                for_each_cpu(i, policy->cpus)
Shouldn't we simply do this instead at the top of this function?
Quoted 2 lines
(quoted diff) +2 -0
+       if (!policy->governor_enabled)
+              return;

Sure that works just as well. Here's a patch.

 drivers/cpufreq/cpufreq_governor.c | 3 +++
 1 file changed, 3 insertions(+)

drivers/cpufreq/cpufreq_governor.c +3 -0

index 7b839a8..b9b20fd 100644
@@ -133,6 +133,9 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 {
 	int i;
 
+	if (!policy->governor_enabled)
+		return;
+
 	if (!all_cpus) {
 		__gov_queue_work(smp_processor_id(), dbs_data, delay);
 	} else {

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Stephen Boyd

author

2013-08-27 22:01 UTC #3 lore raw

PATCH 1/1 cpufreq: Don't use smp_processor_id() in preemptible context

Workqueues are preemptible even if works are queued on them with queue_work_on(). Let's just use the policy->cpu argument here instead of using smp_processor_id() to silence the warning.

BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674
caller is gov_queue_work+0x28/0xb0
CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G        W    3.10.0 #30
Workqueue: events od_dbs_timer
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c03885a4>] (debug_smp_processor_id+0xbc/0xf0)
[<c03885a4>] (debug_smp_processor_id+0xbc/0xf0) from [<c0635864>] (gov_queue_work+0x28/0xb0)
[<c0635864>] (gov_queue_work+0x28/0xb0) from [<c0635618>] (od_dbs_timer+0x108/0x134)
[<c0635618>] (od_dbs_timer+0x108/0x134) from [<c01aa8f8>] (process_one_work+0x25c/0x444)
[<c01aa8f8>] (process_one_work+0x25c/0x444) from [<c01aaf88>] (worker_thread+0x200/0x344)
[<c01aaf88>] (worker_thread+0x200/0x344) from [<c01b03bc>] (kthread+0xa0/0xb0)
[<c01b03bc>] (kthread+0xa0/0xb0) from [<c01061b8>] (ret_from_fork+0x14/0x3c)

Signed-off-by Stephen Boyd <[email protected]>

---

Also found this one. I'm tracking down a pretty bad hotplug/sysfs race on 3.10. I've applied all the stable patches but I'm seeing this still. I'll start another thread on this

WARNING: at kernel/mutex.c:341 __mutex_lock_slowpath+0x14c/0x410()
DEBUG_LOCKS_WARN_ON(l->magic != l)
Modules linked in:
CPU: 0 PID: 1960 Comm: sh Tainted: G        W    3.10.0 #32
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c01904cc>] (warn_slowpath_common+0x4c/0x6c)
[<c01904cc>] (warn_slowpath_common+0x4c/0x6c) from [<c019056c>] (warn_slowpath_fmt+0x2c/0x3c)
[<c019056c>] (warn_slowpath_fmt+0x2c/0x3c) from [<c08a0334>] (__mutex_lock_slowpath+0x14c/0x410)
[<c08a0334>] (__mutex_lock_slowpath+0x14c/0x410) from [<c08a0618>] (mutex_lock+0x20/0x3c)
[<c08a0618>] (mutex_lock+0x20/0x3c) from [<c0636114>] (cpufreq_governor_dbs+0x568/0x5f8)
[<c0636114>] (cpufreq_governor_dbs+0x568/0x5f8) from [<c06325b0>] (__cpufreq_governor+0xdc/0x1a4)
[<c06325b0>] (__cpufreq_governor+0xdc/0x1a4) from [<c06328f0>] (__cpufreq_set_policy+0x278/0x2c0)
[<c06328f0>] (__cpufreq_set_policy+0x278/0x2c0) from [<c0632ea0>] (store_scaling_min_freq+0x80/0x9c)
[<c0632ea0>] (store_scaling_min_freq+0x80/0x9c) from [<c0633ae4>] (store+0x58/0x90)
[<c0633ae4>] (store+0x58/0x90) from [<c02a69d4>] (sysfs_write_file+0x100/0x148)
[<c02a69d4>] (sysfs_write_file+0x100/0x148) from [<c0255c18>] (vfs_write+0xcc/0x174)
[<c0255c18>] (vfs_write+0xcc/0x174) from [<c0255f70>] (SyS_write+0x38/0x64)
[<c0255f70>] (SyS_write+0x38/0x64) from [<c0106120>] (ret_fast_syscall+0x0/0x30)

 drivers/cpufreq/cpufreq_governor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/cpufreq/cpufreq_governor.c +1 -1

index b9b20fd..523af48 100644
@@ -137,7 +137,7 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 		return;
 
 	if (!all_cpus) {
-		__gov_queue_work(smp_processor_id(), dbs_data, delay);
+		__gov_queue_work(policy->cpu, dbs_data, delay);
 	} else {
 		for_each_cpu(i, policy->cpus)
 			__gov_queue_work(i, dbs_data, delay);

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Viresh Kumar

maintainer

2013-08-28 06:34 UTC #4 lore raw

Re: [PATCH] cpufreq: Don't use smp_processor_id() in preemptible context

drivers/cpufreq/cpufreq_governor.c void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, · line 140

Quoted 10 lines · Stephen Boyd

drivers/cpufreq/cpufreq_governor.c +1 -1

index b9b20fd..523af48 100644
@@ -137,7 +137,7 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
                return;
 
        if (!all_cpus) {
-               __gov_queue_work(smp_processor_id(), dbs_data, delay);
+               __gov_queue_work(policy->cpu, dbs_data, delay);

This is probably wrong.. We wanted to queue work on current cpu and not policy->cpu.. Can you use raw_smp_processor_id()?

Quoted 7 lines

drivers/cpufreq/cpufreq_governor.c +0 -1
        } else {
                for_each_cpu(i, policy->cpus)
                        __gov_queue_work(i, dbs_data, delay);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation

Stephen Boyd

author

2013-08-28 16:26 UTC #5 lore raw

Re: [PATCH] cpufreq: Don't use smp_processor_id() in preemptible context

Quoted 8 lines · Viresh Kumar

Quoted 7 lines · Stephen Boyd

drivers/cpufreq/cpufreq_governor.c +0 -0

index b9b20fd..523af48 100644
@@ -137,7 +137,7 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
                return;

Quoted 5 lines

drivers/cpufreq/cpufreq_governor.c void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, · line 140
Quoted 3 lines
drivers/cpufreq/cpufreq_governor.c +1 -1
        if (!all_cpus) {
-               __gov_queue_work(smp_processor_id(), dbs_data, delay);
+               __gov_queue_work(policy->cpu, dbs_data, delay);
This is probably wrong.. We wanted to queue work on current cpu and not policy->cpu.. Can you use raw_smp_processor_id()?

Ah right, for the case where the policy covers more than one cpu. raw_smp_processor_id() would work but it probably also needs a large comment. I'll resend with that.

Signature · 2 lines

Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

Stephen Boyd

author

2013-08-28 21:24 UTC #6 lore raw

PATCH v2 1/1 cpufreq: Don't use smp_processor_id() in preemptible context

Workqueues are preemptible even if works are queued on them with queue_work_on(). Let's use raw_smp_processor_id() here to silence the warning.

BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674
caller is gov_queue_work+0x28/0xb0
CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G        W    3.10.0 #30
Workqueue: events od_dbs_timer
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c03885a4>] (debug_smp_processor_id+0xbc/0xf0)
[<c03885a4>] (debug_smp_processor_id+0xbc/0xf0) from [<c0635864>] (gov_queue_work+0x28/0xb0)
[<c0635864>] (gov_queue_work+0x28/0xb0) from [<c0635618>] (od_dbs_timer+0x108/0x134)
[<c0635618>] (od_dbs_timer+0x108/0x134) from [<c01aa8f8>] (process_one_work+0x25c/0x444)
[<c01aa8f8>] (process_one_work+0x25c/0x444) from [<c01aaf88>] (worker_thread+0x200/0x344)
[<c01aaf88>] (worker_thread+0x200/0x344) from [<c01b03bc>] (kthread+0xa0/0xb0)
[<c01b03bc>] (kthread+0xa0/0xb0) from [<c01061b8>] (ret_from_fork+0x14/0x3c)

Signed-off-by Stephen Boyd <[email protected]>

---
 drivers/cpufreq/cpufreq_governor.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

drivers/cpufreq/cpufreq_governor.c +8 -1

index b9b20fd..bfbcf9a 100644
@@ -137,7 +137,14 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 		return;
 
 	if (!all_cpus) {
-		__gov_queue_work(smp_processor_id(), dbs_data, delay);
+		/*
+		 * Use raw_smp_processor_id() to avoid preemptible warnings.
+		 * We know that this is only called with all_cpus == false from
+		 * works that have been queued with *_work_on() functions and
+		 * those works are canceled during CPU_DOWN_PREPARE so they
+		 * can't possibly run on any other CPU.
+		 */
+		__gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
 	} else {
 		for_each_cpu(i, policy->cpus)
 			__gov_queue_work(i, dbs_data, delay);

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Viresh Kumar

maintainer Acked-by on v2 1/1

2013-08-29 04:20 UTC #7 lore raw

Re: [PATCH v2] cpufreq: Don't use smp_processor_id() in preemptible context

Quoted 17 lines · Stephen Boyd

Workqueues are preemptible even if works are queued on them with queue_work_on(). Let's use raw_smp_processor_id() here to silence the warning.

BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674
caller is gov_queue_work+0x28/0xb0
CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G        W    3.10.0 #30
Workqueue: events od_dbs_timer
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c03885a4>] (debug_smp_processor_id+0xbc/0xf0)
[<c03885a4>] (debug_smp_processor_id+0xbc/0xf0) from [<c0635864>] (gov_queue_work+0x28/0xb0)
[<c0635864>] (gov_queue_work+0x28/0xb0) from [<c0635618>] (od_dbs_timer+0x108/0x134)
[<c0635618>] (od_dbs_timer+0x108/0x134) from [<c01aa8f8>] (process_one_work+0x25c/0x444)
[<c01aa8f8>] (process_one_work+0x25c/0x444) from [<c01aaf88>] (worker_thread+0x200/0x344)
[<c01aaf88>] (worker_thread+0x200/0x344) from [<c01b03bc>] (kthread+0xa0/0xb0)
[<c01b03bc>] (kthread+0xa0/0xb0) from [<c01061b8>] (ret_from_fork+0x14/0x3c)

Quoted 4 lines

Signed-off-by Stephen Boyd <[email protected]>
---
 drivers/cpufreq/cpufreq_governor.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Acked-by Viresh Kumar <[email protected]>

Rafael J. Wysocki

Applied

2013-08-29 20:20 UTC #8 lore raw

Re: [PATCH v2] cpufreq: Don't use smp_processor_id() in preemptible context

Quoted 18 lines · Viresh Kumar

Quoted 17 lines · Stephen Boyd

Workqueues are preemptible even if works are queued on them with queue_work_on(). Let's use raw_smp_processor_id() here to silence the warning.

BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674
caller is gov_queue_work+0x28/0xb0
CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G        W    3.10.0 #30
Workqueue: events od_dbs_timer
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c03885a4>] (debug_smp_processor_id+0xbc/0xf0)
[<c03885a4>] (debug_smp_processor_id+0xbc/0xf0) from [<c0635864>] (gov_queue_work+0x28/0xb0)
[<c0635864>] (gov_queue_work+0x28/0xb0) from [<c0635618>] (od_dbs_timer+0x108/0x134)
[<c0635618>] (od_dbs_timer+0x108/0x134) from [<c01aa8f8>] (process_one_work+0x25c/0x444)
[<c01aa8f8>] (process_one_work+0x25c/0x444) from [<c01aaf88>] (worker_thread+0x200/0x344)
[<c01aaf88>] (worker_thread+0x200/0x344) from [<c01b03bc>] (kthread+0xa0/0xb0)
[<c01b03bc>] (kthread+0xa0/0xb0) from [<c01061b8>] (ret_from_fork+0x14/0x3c)

Quoted 6 lines

Quoted 4 lines
Signed-off-by Stephen Boyd <[email protected]>
---
 drivers/cpufreq/cpufreq_governor.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
Acked-by Viresh Kumar <[email protected]>

Queued up for 3.12, thanks!

Signature · 2 lines

I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Viresh Kumar

maintainer Acked-by on v1 1/1

2013-08-28 05:37 UTC #9 lore raw

In reply to Stephen Boyd

Quoted 10 lines · Stephen Boyd

Sure that works just as well. Here's a patch.
 drivers/cpufreq/cpufreq_governor.c | 3 +++
 1 file changed, 3 insertions(+)
drivers/cpufreq/cpufreq_governor.c +0 -0
index 7b839a8..b9b20fd 100644

drivers/cpufreq/cpufreq_governor.c void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, · line 141

Quoted 9 lines

drivers/cpufreq/cpufreq_governor.c +3 -0

@@ -133,6 +133,9 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 {
        int i;
 
+       if (!policy->governor_enabled)
+               return;
+
        if (!all_cpus) {
                __gov_queue_work(smp_processor_id(), dbs_data, delay);
        } else {

Acked-by Viresh Kumar <[email protected]>