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* cpufreq: fix bad unlock balance on !CONFIG_SMPLi Zhong2013-08-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch tries to fix lockdep complaint attached below. It seems that we should always read acquire the cpufreq_rwsem, whether CONFIG_SMP is enabled or not. And CONFIG_HOTPLUG_CPU depends on CONFIG_SMP, so it seems we don't need CONFIG_SMP for the code enabled by CONFIG_HOTPLUG_CPU. [ 0.504191] ===================================== [ 0.504627] [ BUG: bad unlock balance detected! ] [ 0.504627] 3.11.0-rc6-next-20130819 #1 Not tainted [ 0.504627] ------------------------------------- [ 0.504627] swapper/1 is trying to release lock (cpufreq_rwsem) at: [ 0.504627] [<ffffffff813d927a>] cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] but there are no more locks to release! [ 0.504627] [ 0.504627] other info that might help us debug this: [ 0.504627] 1 lock held by swapper/1: [ 0.504627] #0: (subsys mutex#4){+.+.+.}, at: [<ffffffff8134a7bf>] subsys_interface_register+0x4f/0xe0 [ 0.504627] [ 0.504627] stack backtrace: [ 0.504627] CPU: 0 PID: 1 Comm: swapper Not tainted 3.11.0-rc6-next-20130819 #1 [ 0.504627] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 0.504627] ffffffff813d927a ffff88007f847c98 ffffffff814c062b ffff88007f847cc8 [ 0.504627] ffffffff81098bce ffff88007f847cf8 ffffffff81aadc30 ffffffff813d927a [ 0.504627] 00000000ffffffff ffff88007f847d68 ffffffff8109d0be 0000000000000006 [ 0.504627] Call Trace: [ 0.504627] [<ffffffff813d927a>] ? cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [<ffffffff814c062b>] dump_stack+0x19/0x1b [ 0.504627] [<ffffffff81098bce>] print_unlock_imbalance_bug+0xfe/0x110 [ 0.504627] [<ffffffff813d927a>] ? cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [<ffffffff8109d0be>] lock_release_non_nested+0x1ee/0x310 [ 0.504627] [<ffffffff81099d0e>] ? mark_held_locks+0xae/0x120 [ 0.504627] [<ffffffff811510cb>] ? kfree+0xcb/0x1d0 [ 0.504627] [<ffffffff813d77ea>] ? cpufreq_policy_free+0x4a/0x60 [ 0.504627] [<ffffffff813d927a>] ? cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [<ffffffff8109d2a4>] lock_release+0xc4/0x250 [ 0.504627] [<ffffffff8106c9f3>] up_read+0x23/0x40 [ 0.504627] [<ffffffff813d927a>] cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [<ffffffff8134a809>] subsys_interface_register+0x99/0xe0 [ 0.504627] [<ffffffff81b19f3b>] ? cpufreq_gov_dbs_init+0x12/0x12 [ 0.504627] [<ffffffff813d7f0d>] cpufreq_register_driver+0x9d/0x1d0 [ 0.504627] [<ffffffff81b19f3b>] ? cpufreq_gov_dbs_init+0x12/0x12 [ 0.504627] [<ffffffff81b1a039>] acpi_cpufreq_init+0xfe/0x1f8 [ 0.504627] [<ffffffff810002ba>] do_one_initcall+0xda/0x180 [ 0.504627] [<ffffffff81ae301e>] kernel_init_freeable+0x12c/0x1bb [ 0.504627] [<ffffffff81ae2841>] ? do_early_param+0x8c/0x8c [ 0.504627] [<ffffffff814b4dd0>] ? rest_init+0x140/0x140 [ 0.504627] [<ffffffff814b4dde>] kernel_init+0xe/0xf0 [ 0.504627] [<ffffffff814d029a>] ret_from_fork+0x7a/0xb0 [ 0.504627] [<ffffffff814b4dd0>] ? rest_init+0x140/0x140 Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Acked-and-tested-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Use cpufreq_policy_list for iterating over policiesViresh Kumar2013-08-201-5/+4Star
| | | | | | | | | To iterate over all policies we currently iterate over all online CPUs and then get the policy for each of them which is suboptimal. Use the newly created cpufreq_policy_list for this purpose instead. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: remove cpufreq_policy_cpu per-cpu variableViresh Kumar2013-08-201-35/+10Star
| | | | | | | | | | | | | | | cpufreq_policy_cpu per-cpu variables are used for storing the ID of the CPU that manages the given CPU's policy. However, we also store a policy pointer for each cpu in cpufreq_cpu_data, so the cpufreq_policy_cpu information is simply redundant. It is better to use cpufreq_cpu_data to retrieve a policy and get policy->cpu from there, so make that happen everywhere and drop the cpufreq_policy_cpu per-cpu variables which aren't necessary any more. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: remove unnecessary check in __cpufreq_governor()Viresh Kumar2013-08-201-2/+0Star
| | | | | | | | | | We don't need to check if event is CPUFREQ_GOV_POLICY_INIT and put governor module as we are sure event can only be START/STOP here. Remove the useless check. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: remove policy from cpufreq_policy_list during suspendViresh Kumar2013-08-201-10/+9Star
| | | | | | | | | | | | | | | | | | | | cpufreq_policy_list is a list of active policies. We do remove policies from this list when all CPUs belonging to that policy are removed. But during system suspend we don't really free a policy struct as it will be used again during resume, so we didn't remove it from cpufreq_policy_list as well.. However, this is incorrect. We are saying this policy isn't valid anymore and must not be referenced (though we haven't freed it), but it can still be used by code that iterates over cpufreq_policy_list. Remove policy from this list during system suspend as well. Of course, we must add it back whenever the first CPU belonging to that policy shows up. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Fix white space in __cpufreq_remove_dev()Viresh Kumar2013-08-201-1/+1
| | | | | | | | Align closing brace '}' of an if block. [rjw: Subject and changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Revert "cpufreq: Use cpufreq_policy_list for iterating over policies"Rafael J. Wysocki2013-08-181-4/+5
| | | | | | | | | | | | | Revert commit eb60852 (cpufreq: Use cpufreq_policy_list for iterating over policies), because it breaks system suspend/resume on multiple machines. It either causes resume to block indefinitely or causes the BUG_ON() in lock_policy_rwsem_##mode() to trigger on sysfs accesses to cpufreq attributes. Conflicts: drivers/cpufreq/cpufreq.c
* cpufreq: improve error checking on return values of __cpufreq_governor()Viresh Kumar2013-08-101-12/+36
| | | | | | | | | | | | | The __cpufreq_governor() function can fail in rare cases especially if there are bugs in cpufreq drivers. Thus we must stop processing as soon as this routine fails, otherwise it may result in undefined behavior. This patch adds error checking code whenever this routine is called from any place. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Use rwsem for protecting critical sectionsViresh Kumar2013-08-101-78/+57Star
| | | | | | | | | | | | | | | Critical sections of the cpufreq core are protected with the help of the driver module owner's refcount, which isn't the correct approach, because it causes rmmod to return an error when some routine has updated that refcount. Let's use rwsem for this purpose instead. Only cpufreq_unregister_driver() will use write sem and everybody else will use read sem. [rjw: Subject & changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Fix broken usage of governor->owner's refcountViresh Kumar2013-08-101-7/+7
| | | | | | | | | | | | | The cpufreq governor owner refcount usage is broken. We should only increment that refcount when a CPUFREQ_GOV_POLICY_INIT event has come and it should only be decremented if CPUFREQ_GOV_POLICY_EXIT has come. Currently, there can be situations where the governor is in use, but we have allowed it to be unloaded which may result in undefined behavior. Let's fix it. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Use cpufreq_policy_list for iterating over policiesViresh Kumar2013-08-101-5/+5
| | | | | | | | | | To iterate over all policies we currently iterate over all CPUs and then get the policy for each of them. Let's use the newly created cpufreq_policy_list for this purpose. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Store cpufreq policies in a listLukasz Majewski2013-08-101-0/+12
| | | | | | | | | | | | Policies available in the cpufreq framework are now linked together. They are accessible via cpufreq_policy_list defined in the cpufreq core. [rjw: Fix from Yinghai Lu folded in] Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Use sizeof(*ptr) convetion for computing sizesViresh Kumar2013-08-071-5/+4Star
| | | | | | | | | | | | | | | | | | | Chapter 14 of Documentation/CodingStyle says: The preferred form for passing a size of a struct is the following: p = kmalloc(sizeof(*p), ...); The alternative form where struct name is spelled out hurts readability and introduces an opportunity for a bug when the pointer variable type is changed but the corresponding sizeof that is passed to a memory allocator is not. This wasn't followed consistently in drivers/cpufreq, let's make it more consistent by always following this rule. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Give consistent names to cpufreq_policy objectsViresh Kumar2013-08-071-100/+100
| | | | | | | | They are called policy, cur_policy, new_policy, data, etc. Just call them policy wherever possible. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Clean up header files included in the coreViresh Kumar2013-08-071-13/+6Star
| | | | | | | | | | | | | | | | This patch addresses the following issues in the header files in the cpufreq core: - Include headers in ascending order, so that we don't add same many times by mistake. - <asm/> must be included after <linux/>, so that they override whatever they need to. - Remove unnecessary includes. - Don't include files already included by cpufreq.h or cpufreq_governor.h. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge branch 'pm-cpufreq-ondemand' into pm-cpufreqRafael J. Wysocki2013-08-071-12/+0Star
|\ | | | | | | | | | | | | * pm-cpufreq: cpufreq: Remove unused function __cpufreq_driver_getavg() cpufreq: Remove unused APERF/MPERF support cpufreq: ondemand: Change the calculation of target frequency
| * cpufreq: Remove unused function __cpufreq_driver_getavg()Stratos Karafotis2013-07-261-12/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | The target frequency calculation method in the ondemand governor has changed and it is now independent of the measured average frequency. Consequently, the __cpufreq_driver_getavg() function and getavg member of struct cpufreq_driver are not used any more, so drop them. [rjw: Changelog] Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Pass policy to cpufreq_add_policy_cpu()Viresh Kumar2013-08-071-12/+6Star
| | | | | | | | | | | | | | | | | | | | The caller of cpufreq_add_policy_cpu() already has a pointer to the policy structure and there is no need to look it up again in cpufreq_add_policy_cpu(). Let's pass it directly. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Avoid double kobject_put() for the same kobject in error code pathRafael J. Wysocki2013-08-071-3/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The only case triggering a jump to the err_out_unregister label in __cpufreq_add_dev() is when cpufreq_add_dev_interface() fails. However, if cpufreq_add_dev_interface() fails, it calls kobject_put() for the policy kobject in its error code path and since that causes the kobject's refcount to become 0, the additional kobject_put() for the same kobject under err_out_unregister and the wait_for_completion() following it are pointless, so drop them. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
* | cpufreq: Do not hold driver module references for additional policy CPUsRafael J. Wysocki2013-08-071-21/+7Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The cpufreq core is a little inconsistent in the way it uses the driver module refcount. Namely, if __cpufreq_add_dev() is called for a CPU that doesn't share the policy object with any other CPUs, the driver module refcount it grabs to start with will be dropped by it before returning and will be equal to whatever it had been before that function was invoked. However, if the given CPU does share the policy object with other CPUs, either cpufreq_add_policy_cpu() is called to link the new CPU to the existing policy, or cpufreq_add_dev_symlink() is used to link the other CPUs sharing the policy with it to the just created policy object. In that case, because both cpufreq_add_policy_cpu() and cpufreq_add_dev_symlink() call cpufreq_cpu_get() for the given policy (the latter possibly many times) without the balancing cpufreq_cpu_put() (unless there is an error), the driver module refcount will be left by __cpufreq_add_dev() with a nonzero value (different from the initial one). To remove that inconsistency make cpufreq_add_policy_cpu() execute cpufreq_cpu_put() for the given policy before returning, which decrements the driver module refcount so that it will be equal to its initial value after __cpufreq_add_dev() returns. Also remove the cpufreq_cpu_get() call from cpufreq_add_dev_symlink(), since both the policy refcount and the driver module refcount are nonzero when it is called and they don't need to be bumped up by it. Accordingly, drop the cpufreq_cpu_put() from __cpufreq_remove_dev(), since it is only necessary to balance the cpufreq_cpu_get() called by cpufreq_add_policy_cpu() or cpufreq_add_dev_symlink(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
* | cpufreq: Don't pass CPU to cpufreq_add_dev_{symlink|interface}()Viresh Kumar2013-08-071-8/+6Star
| | | | | | | | | | | | | | | | | | Pointer to struct cpufreq_policy is already passed to these routines and we don't need to send policy->cpu to them as well. So, get rid of this extra argument and use policy->cpu everywhere. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Remove extra variables from cpufreq_add_dev_symlink()Viresh Kumar2013-08-071-4/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | We call cpufreq_cpu_get() in cpufreq_add_dev_symlink() to increase usage refcount of policy, but not to get a policy for the given CPU. So, we don't really need to capture the return value of this routine. We can simply use policy passed as an argument to cpufreq_add_dev_symlink(). Moreover debug print is rewritten to make it more clear. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Perform light-weight init/teardown during suspend/resumeSrivatsa S. Bhat2013-08-071-7/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we have the infrastructure to perform a light-weight init/tear-down, use that in the cpufreq CPU hotplug notifier when invoked from the suspend/resume path. This also ensures that the file permissions of the cpufreq sysfs files are preserved across suspend/resume, something which commit a66b2e (cpufreq: Preserve sysfs files across suspend/resume) originally intended to do, but had to be reverted due to other problems. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Preserve policy structure across suspend/resumeSrivatsa S. Bhat2013-08-071-16/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To perform light-weight cpu-init and teardown in the cpufreq subsystem during suspend/resume, we need to separate out the 2 main functionalities of the cpufreq CPU hotplug callbacks, as outlined below: 1. Init/tear-down of core cpufreq and CPU-specific components, which are critical to the correct functioning of the cpufreq subsystem. 2. Init/tear-down of cpufreq sysfs files during suspend/resume. The first part requires accurate updates to the policy structure such as its ->cpus and ->related_cpus masks, whereas the second part requires that the policy->kobj structure is not released or re-initialized during suspend/resume. To handle both these requirements, we need to allow updates to the policy structure throughout suspend/resume, but prevent the structure from getting freed up. Also, we must have a mechanism by which the cpu-up callbacks can restore the policy structure, without allocating things afresh. (That also helps avoid memory leaks). To achieve this, we use 2 schemes: a. Use a fallback per-cpu storage area for preserving the policy structures during suspend, so that they can be restored during resume appropriately. b. Use the 'frozen' flag to determine when to free or allocate the policy structure vs when to restore the policy from the saved fallback storage. Thus we can successfully preserve the structure across suspend/resume. Effectively, this helps us complete the separation of the 'light-weight' and the 'full' init/tear-down sequences in the cpufreq subsystem, so that this can be made use of in the suspend/resume scenario. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Introduce a flag ('frozen') to separate full vs temporary init/teardownSrivatsa S. Bhat2013-08-071-27/+49
| | | | | | | | | | | | | | | | | | | | | | During suspend/resume we would like to do a light-weight init/teardown of CPUs in the cpufreq subsystem and preserve certain things such as sysfs files etc across suspend/resume transitions. Add a flag called 'frozen' to help distinguish the full init/teardown sequence from the light-weight one. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Extract the handover of policy cpu to a helper functionSrivatsa S. Bhat2013-08-071-24/+39
| | | | | | | | | | | | | | | | | | | | | | During cpu offline, when the policy->cpu is going down, some other CPU present in the policy->cpus mask is nominated as the new policy->cpu. Extract this functionality from __cpufreq_remove_dev() and implement it in a helper function. This helps in upcoming code reorganization. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Extract non-interface related stuff from cpufreq_add_dev_interfaceSrivatsa S. Bhat2013-08-071-17/+26
| | | | | | | | | | | | | | | | | | | | cpufreq_add_dev_interface() includes the work of exposing the interface to the device, as well as a lot of unrelated stuff. Move the latter to cpufreq_add_dev(), where it is more appropriate. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Add helper to perform alloc/free of policy structureSrivatsa S. Bhat2013-08-071-15/+34
| | | | | | | | | | | | | | | | | | | | Separate out the allocation of the cpufreq policy structure (along with its error handling) to a helper function. This makes the code easier to read and also helps with some upcoming code reorganization. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Fix misplaced call to cpufreq_update_policy()Srivatsa S. Bhat2013-08-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The call to cpufreq_update_policy() is placed in the CPU hotplug callback of cpufreq_stats, which has a higher priority than the CPU hotplug callback of cpufreq-core. As a result, during CPU_ONLINE/CPU_ONLINE_FROZEN, we end up calling cpufreq_update_policy() *before* calling cpufreq_add_dev() ! And for uninitialized CPUs, it just returns silently, not doing anything. To add to that, cpufreq_stats is not even the right place to call cpufreq_update_policy() to begin with. The cpufreq core ought to handle this in its own callback, from an elegance/relevance perspective. So move the invocation of cpufreq_update_policy() to cpufreq_cpu_callback, and place it *after* cpufreq_add_dev(). Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: Fix cpufreq driver module refcount balance after suspend/resumeRafael J. Wysocki2013-07-301-9/+10
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the driver module refcount, __cpufreq_remove_dev() causes that refcount to become negative for the cpufreq driver after a suspend/resume cycle. This is not the only bad thing that happens there, however, because kobject_put() should only be called for the policy kobject at this point if the CPU is not the last one for that policy. Namely, if the given CPU is the last one for that policy, the policy kobject's refcount should be 1 at this point, as set by cpufreq_add_dev_interface(), and only needs to be dropped once for the kobject to go away. This actually happens under the cpu == 1 check, so it need not be done before by cpufreq_cpu_put(). On the other hand, if the given CPU is not the last one for that policy, this means that cpufreq_add_policy_cpu() has been called at least once for that policy and cpufreq_cpu_get() has been called for it too. To balance that cpufreq_cpu_get(), we need to call cpufreq_cpu_put() in that case. Thus, to fix the described problem and keep the reference counters balanced in both cases, move the cpufreq_cpu_get() call in __cpufreq_remove_dev() to the code path executed only for CPUs that share the policy with other CPUs. Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: 3.10+ <stable@vger.kernel.org>
* Merge tag 'pm+acpi-3.11-rc2' of ↵Linus Torvalds2013-07-191-1/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI fixes from Rafael Wysocki: "These are fixes collected over the last week, most importnatly two cpufreq reverts fixing regressions introduced in 3.10, an autoseelp fix preventing systems using it from crashing during shutdown and two ACPI scan fixes related to hotplug. Specifics: - Two cpufreq commits from the 3.10 cycle introduced regressions. The first of them was buggy (it did way much more than it needed to do) and the second one attempted to fix an issue introduced by the first one. Fixes from Srivatsa S Bhat revert both. - If autosleep triggers during system shutdown and the shutdown callbacks of some device drivers have been called already, it may crash the system. Fix from Liu Shuo prevents that from happening by making try_to_suspend() check system_state. - The ACPI memory hotplug driver doesn't clear its driver_data on errors which may cause a NULL poiter dereference to happen later. Fix from Toshi Kani. - The ACPI namespace scanning code should not try to attach scan handlers to device objects that have them already, which may confuse things quite a bit, and it should rescan the whole namespace branch starting at the given node after receiving a bus check notify event even if the device at that particular node has been discovered already. Fixes from Rafael J Wysocki. - New ACPI video blacklist entry for a system whose initial backlight setting from the BIOS doesn't make sense. From Lan Tianyu. - Garbage string output avoindance for ACPI PNP from Liu Shuo. - Two Kconfig fixes for issues introduced recently in the s3c24xx cpufreq driver (when moving the driver to drivers/cpufreq) from Paul Bolle. - Trivial comment fix in pm_wakeup.h from Chanwoo Choi" * tag 'pm+acpi-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI / video: ignore BIOS initial backlight value for Fujitsu E753 PNP / ACPI: avoid garbage in resource name cpufreq: Revert commit 2f7021a8 to fix CPU hotplug regression cpufreq: s3c24xx: fix "depends on ARM_S3C24XX" in Kconfig cpufreq: s3c24xx: rename CONFIG_CPU_FREQ_S3C24XX_DEBUGFS PM / Sleep: Fix comment typo in pm_wakeup.h PM / Sleep: avoid 'autosleep' in shutdown progress cpufreq: Revert commit a66b2e to fix suspend/resume regression ACPI / memhotplug: Fix a stale pointer in error path ACPI / scan: Always call acpi_bus_scan() for bus check notifications ACPI / scan: Do not try to attach scan handlers to devices having them
| * cpufreq: Revert commit a66b2e to fix suspend/resume regressionSrivatsa S. Bhat2013-07-151-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a66b2e (cpufreq: Preserve sysfs files across suspend/resume) has unfortunately caused several things in the cpufreq subsystem to break subtly after a suspend/resume cycle. The intention of that patch was to retain the file permissions of the cpufreq related sysfs files across suspend/resume. To achieve that, the commit completely removed the calls to cpufreq_add_dev() and __cpufreq_remove_dev() during suspend/resume transitions. But the problem is that those functions do 2 kinds of things: 1. Low-level initialization/tear-down that are critical to the correct functioning of cpufreq-core. 2. Kobject and sysfs related initialization/teardown. Ideally we should have reorganized the code to cleanly separate these two responsibilities, and skipped only the sysfs related parts during suspend/resume. Since we skipped the entire callbacks instead (which also included some CPU and cpufreq-specific critical components), cpufreq subsystem started behaving erratically after suspend/resume. So revert the commit to fix the regression. We'll revisit and address the original goal of that commit separately, since it involves quite a bit of careful code reorganization and appears to be non-trivial. (While reverting the commit, note that another commit f51e1eb (cpufreq: Fix cpufreq regression after suspend/resume) already reverted part of the original set of changes. So revert only the remaining ones). Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Tested-by: Paul Bolle <pebolle@tiscali.nl> Cc: 3.10+ <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | cpufreq: delete __cpuinit usage from all cpufreq filesPaul Gortmaker2013-07-151-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. This removes all the drivers/cpufreq uses of the __cpuinit macros from all C files. [1] https://lkml.org/lkml/2013/5/20/589 [v2: leave 2nd lines of args misaligned as requested by Viresh] Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: cpufreq@vger.kernel.org Cc: linux-pm@vger.kernel.org Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* cpufreq: Fix serialization of frequency transitionsViresh Kumar2013-07-041-3/+4
| | | | | | | | | | | | | | | | | | Commit 7c30ed ("cpufreq: make sure frequency transitions are serialized") interacts poorly with systems that have a single core freqency for all cores. On such systems we have a single policy for all cores with several CPUs. When we do a frequency transition the governor calls the pre and post change notifiers which causes cpufreq_notify_transition() per CPU. Since the policy is the same for all of them all CPUs after the first and the warnings added are generated by checking a per-policy flag the warnings will be triggered for all cores after the first. Fix this by allowing notifier to be called for n times. Where n is the number of cpus in policy->cpus. Reported-and-tested-by: Mark Brown <broonie@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* acpi-cpufreq: Add new sysfs attribute freqdomain_cpusLan Tianyu2013-06-271-3/+4
| | | | | | | | | | | | | | | | | | | | | Commits fcf8058 (cpufreq: Simplify cpufreq_add_dev()) and aa77a52 (cpufreq: acpi-cpufreq: Don't set policy->related_cpus from .init()) changed the contents of the "related_cpus" sysfs attribute on systems where acpi-cpufreq is used and user space can't get the list of CPUs which are in the same hardware coordination CPU domain (provided by the ACPI AML method _PSD) via "related_cpus" any more. To make up for that loss add a new sysfs attribute "freqdomian_cpus" for the acpi-cpufreq driver which exposes the list of CPUs in the same domain regardless of whether it is coordinated by hardware or software. [rjw: Changelog, documentation] References: https://bugzilla.kernel.org/show_bug.cgi?id=58761 Reported-by: Jean-Philippe Halimi <jean-philippe.halimi@exascale-computing.eu> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: make sure frequency transitions are serializedViresh Kumar2013-06-271-0/+14
| | | | | | | | | | | | | | | Whenever we are changing frequency of a cpu, we are calling PRECHANGE and POSTCHANGE notifiers. They must be serialized. i.e. PRECHANGE or POSTCHANGE shouldn't be called twice contiguously. This can happen due to bugs in users of __cpufreq_driver_target() or actual cpufreq drivers who are sending these notifiers. This patch adds some protection against this. Now, we keep track of the last transaction and see if something went wrong. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: make __cpufreq_notify_transition() staticViresh Kumar2013-06-211-1/+1
| | | | | | | | __cpufreq_notify_transition() is used only in cpufreq.c, make it static. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Fix minor formatting issuesViresh Kumar2013-06-211-36/+27Star
| | | | | | | | | | | | | | | | There were a few noticeable formatting issues in core cpufreq code. This cleans them up to make code look better. The changes include: - Whitespace cleanup. - Rearrangements of code. - Multiline comments fixes. - Formatting changes to fit 80 columns. Copyright information in cpufreq.c is also updated to include my name for 2013. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Fix governor start/stop race conditionXiaoguang Chen2013-06-211-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cpufreq governors' stop and start operations should be carried out in sequence. Otherwise, there will be unexpected behavior, like in the example below. Suppose there are 4 CPUs and policy->cpu=CPU0, CPU1/2/3 are linked to CPU0. The normal sequence is: 1) Current governor is userspace. An application tries to set the governor to ondemand. It will call __cpufreq_set_policy() in which it will stop the userspace governor and then start the ondemand governor. 2) Current governor is userspace. The online of CPU3 runs on CPU0. It will call cpufreq_add_policy_cpu() in which it will first stop the userspace governor, and then start it again. If the sequence of the above two cases interleaves, it becomes: 1) Application stops userspace governor 2) Hotplug stops userspace governor which is a problem, because the governor shouldn't be stopped twice in a row. What happens next is: 3) Application starts ondemand governor 4) Hotplug starts a governor In step 4, the hotplug is supposed to start the userspace governor, but now the governor has been changed by the application to ondemand, so the ondemand governor is started once again, which is incorrect. The solution is to prevent policy governors from being stopped multiple times in a row. A governor should only be stopped once for one policy. After it has been stopped, no more governor stop operations should be executed. Also add a mutex to serialize governor operations. [rjw: Changelog. And you owe me a beverage of my choice.] Signed-off-by: Xiaoguang Chen <chenxg@marvell.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: remove unnecessary cpufreq_cpu_{get|put}() callsViresh Kumar2013-06-041-17/+2Star
| | | | | | | | | | | | struct cpufreq_policy is already passed as argument to some routines like: __cpufreq_driver_getavg() and so we don't really need to do cpufreq_cpu_get() before and cpufreq_cpu_put() in them to get a policy structure. Remove them. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directoryViresh Kumar2013-05-271-4/+44
| | | | | | | | | | | | | When we don't have any file in cpu/cpufreq directory we shouldn't create it. Specially with the introduction of per-policy governor instance patchset, even governors are moved to cpu/cpu*/cpufreq/governor-name directory and so this directory is just not required. Lets have it only when required. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Move get_cpu_idle_time() to cpufreq.cViresh Kumar2013-05-271-0/+38
| | | | | | | | | | Governors other than ondemand and conservative can also use get_cpu_idle_time() and they aren't required to compile cpufreq_governor.c. So, move these independent routines to cpufreq.c instead. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: governors: Move get_governor_parent_kobj() to cpufreq.cViresh Kumar2013-05-271-0/+9
| | | | | | | | | | | | | get_governor_parent_kobj() can be used by any governor, generic cpufreq governors or platform specific ones and so must be present in cpufreq.c instead of cpufreq_governor.c. This patch moves it to cpufreq.c. This also adds EXPORT_SYMBOL_GPL(get_governor_parent_kobj) so that modules can use this function too. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Add EXPORT_SYMBOL_GPL for have_governor_per_policyViresh Kumar2013-05-271-0/+1
| | | | | | | | This patch adds: EXPORT_SYMBOL_GPL(have_governor_per_policy), so that this routine can be used by modules too. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXITViresh Kumar2013-05-221-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the rwsem lock around __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT), we get circular dependency when we call sysfs_remove_group(). ====================================================== [ INFO: possible circular locking dependency detected ] 3.9.0-rc7+ #15 Not tainted ------------------------------------------------------- cat/2387 is trying to acquire lock: (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at: [<c02f6179>] lock_policy_rwsem_read+0x25/0x34 but task is already holding lock: (s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (s_active#41){++++.+}: [<c0055a79>] lock_acquire+0x61/0xbc [<c00fabf1>] sysfs_addrm_finish+0xc1/0x128 [<c00f9819>] sysfs_hash_and_remove+0x35/0x64 [<c00fbe6f>] remove_files.isra.0+0x1b/0x24 [<c00fbea5>] sysfs_remove_group+0x2d/0xa8 [<c02f9a0b>] cpufreq_governor_interactive+0x13b/0x35c [<c02f61df>] __cpufreq_governor+0x2b/0x8c [<c02f6579>] __cpufreq_set_policy+0xa9/0xf8 [<c02f6b75>] store_scaling_governor+0x61/0x100 [<c02f6f4d>] store+0x39/0x60 [<c00f9b81>] sysfs_write_file+0xed/0x114 [<c00b3fd1>] vfs_write+0x65/0xd8 [<c00b424b>] sys_write+0x2f/0x50 [<c000cdc1>] ret_fast_syscall+0x1/0x52 -> #0 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}: [<c0055253>] __lock_acquire+0xef3/0x13dc [<c0055a79>] lock_acquire+0x61/0xbc [<c03ee1f5>] down_read+0x25/0x30 [<c02f6179>] lock_policy_rwsem_read+0x25/0x34 [<c02f6edd>] show+0x21/0x58 [<c00f9c0f>] sysfs_read_file+0x67/0xcc [<c00b40a7>] vfs_read+0x63/0xd8 [<c00b41fb>] sys_read+0x2f/0x50 [<c000cdc1>] ret_fast_syscall+0x1/0x52 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(s_active#41); lock(&per_cpu(cpu_policy_rwsem, cpu)); lock(s_active#41); lock(&per_cpu(cpu_policy_rwsem, cpu)); *** DEADLOCK *** 2 locks held by cat/2387: #0: (&buffer->mutex){+.+.+.}, at: [<c00f9bcd>] sysfs_read_file+0x25/0xcc #1: (s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc stack backtrace: [<c0011d55>] (unwind_backtrace+0x1/0x9c) from [<c03e9a09>] (print_circular_bug+0x19d/0x1e8) [<c03e9a09>] (print_circular_bug+0x19d/0x1e8) from [<c0055253>] (__lock_acquire+0xef3/0x13dc) [<c0055253>] (__lock_acquire+0xef3/0x13dc) from [<c0055a79>] (lock_acquire+0x61/0xbc) [<c0055a79>] (lock_acquire+0x61/0xbc) from [<c03ee1f5>] (down_read+0x25/0x30) [<c03ee1f5>] (down_read+0x25/0x30) from [<c02f6179>] (lock_policy_rwsem_read+0x25/0x34) [<c02f6179>] (lock_policy_rwsem_read+0x25/0x34) from [<c02f6edd>] (show+0x21/0x58) [<c02f6edd>] (show+0x21/0x58) from [<c00f9c0f>] (sysfs_read_file+0x67/0xcc) [<c00f9c0f>] (sysfs_read_file+0x67/0xcc) from [<c00b40a7>] (vfs_read+0x63/0xd8) [<c00b40a7>] (vfs_read+0x63/0xd8) from [<c00b41fb>] (sys_read+0x2f/0x50) [<c00b41fb>] (sys_read+0x2f/0x50) from [<c000cdc1>] (ret_fast_syscall+0x1/0x52) This lock isn't required while calling __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT). Remove it. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Preserve sysfs files across suspend/resumeSrivatsa S. Bhat2013-05-151-3/+1Star
| | | | | | | | | | | | | | | | | | | | | | The file permissions of cpufreq per-cpu sysfs files are not preserved across suspend/resume because we internally go through the CPU Hotplug path which reinitializes the file permissions on CPU online. But the user is not supposed to know that we are using CPU hotplug internally within suspend/resume (IOW, the kernel should not silently wreck the user-set file permissions across a suspend cycle). Therefore, we need to preserve the file permissions as they are across suspend/resume. The simplest way to achieve that is to just not touch the sysfs files at all - ie., just ignore the CPU hotplug notifications in the suspend/resume path (_FROZEN) in the cpufreq hotplug callback. Reported-by: Robert Jarzmik <robert.jarzmik@intel.com> Reported-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Issue CPUFREQ_GOV_POLICY_EXIT notifier before dropping policy refcountViresh Kumar2013-05-121-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We must call __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT) before calling cpufreq_cpu_put(data), so that policy kobject have valid fields. Otherwise, removing last online cpu of policy->cpus causes this crash for ondemand/conservative governor. [<c00fb076>] (sysfs_find_dirent+0xe/0xa8) from [<c00fb1bd>] (sysfs_get_dirent+0x21/0x58) [<c00fb1bd>] (sysfs_get_dirent+0x21/0x58) from [<c00fc259>] (sysfs_remove_group+0x85/0xbc) [<c00fc259>] (sysfs_remove_group+0x85/0xbc) from [<c02faad9>] (cpufreq_governor_dbs+0x369/0x4a0) [<c02faad9>] (cpufreq_governor_dbs+0x369/0x4a0) from [<c02f66d7>] (__cpufreq_governor+0x2b/0x8c) [<c02f66d7>] (__cpufreq_governor+0x2b/0x8c) from [<c02f6893>] (__cpufreq_remove_dev.isra.12+0x15b/0x250) [<c02f6893>] (__cpufreq_remove_dev.isra.12+0x15b/0x250) from [<c03e91c7>] (cpufreq_cpu_callback+0x2f/0x3c) [<c03e91c7>] (cpufreq_cpu_callback+0x2f/0x3c) from [<c0036fe1>] (notifier_call_chain+0x45/0x54) [<c0036fe1>] (notifier_call_chain+0x45/0x54) from [<c001e611>] (__cpu_notify+0x1d/0x34) [<c001e611>] (__cpu_notify+0x1d/0x34) from [<c03e5833>] (_cpu_down+0x63/0x1ac) [<c03e5833>] (_cpu_down+0x63/0x1ac) from [<c03e5997>] (cpu_down+0x1b/0x30) [<c03e5997>] (cpu_down+0x1b/0x30) from [<c03e60eb>] (store_online+0x27/0x54) [<c03e60eb>] (store_online+0x27/0x54) from [<c0295629>] (dev_attr_store+0x11/0x18) [<c0295629>] (dev_attr_store+0x11/0x18) from [<c00f9edd>] (sysfs_write_file+0xed/0x114) [<c00f9edd>] (sysfs_write_file+0xed/0x114) from [<c00b42a9>] (vfs_write+0x65/0xd8) [<c00b42a9>] (vfs_write+0x65/0xd8) from [<c00b4523>] (sys_write+0x2f/0x50) [<c00b4523>] (sys_write+0x2f/0x50) from [<c000cdc1>] (ret_fast_syscall+0x1/0x52) Of course this only impacted drivers which have have_governor_per_policy set to true. i.e. big LITTLE cpufreq driver. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Revert incorrect commit 5800043Rafael J. Wysocki2013-04-291-214/+69Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 5800043 (cpufreq: convert cpufreq_driver to using RCU) causes the following call trace to be spit on boot: BUG: sleeping function called from invalid context at /scratch/rafael/work/linux-pm/mm/slab.c:3179 in_atomic(): 0, irqs_disabled(): 0, pid: 292, name: systemd-udevd 2 locks held by systemd-udevd/292: #0: (subsys mutex){+.+.+.}, at: [<ffffffff8146851a>] subsys_interface_register+0x4a/0xe0 #1: (rcu_read_lock){.+.+.+}, at: [<ffffffff81538210>] cpufreq_add_dev_interface+0x60/0x5e0 Pid: 292, comm: systemd-udevd Not tainted 3.9.0-rc8+ #323 Call Trace: [<ffffffff81072c90>] __might_sleep+0x140/0x1f0 [<ffffffff811581c2>] kmem_cache_alloc+0x42/0x2b0 [<ffffffff811e7179>] sysfs_new_dirent+0x59/0x130 [<ffffffff811e63cb>] sysfs_add_file_mode+0x6b/0x110 [<ffffffff81538210>] ? cpufreq_add_dev_interface+0x60/0x5e0 [<ffffffff810a3254>] ? __lock_is_held+0x54/0x80 [<ffffffff811e647d>] sysfs_add_file+0xd/0x10 [<ffffffff811e6541>] sysfs_create_file+0x21/0x30 [<ffffffff81538280>] cpufreq_add_dev_interface+0xd0/0x5e0 [<ffffffff81538210>] ? cpufreq_add_dev_interface+0x60/0x5e0 [<ffffffffa000337f>] ? acpi_processor_get_platform_limit+0x32/0xbb [processor] [<ffffffffa022f540>] ? do_drv_write+0x70/0x70 [acpi_cpufreq] [<ffffffff810a3254>] ? __lock_is_held+0x54/0x80 [<ffffffff8106c97e>] ? up_read+0x1e/0x40 [<ffffffff8106e632>] ? __blocking_notifier_call_chain+0x72/0xc0 [<ffffffff81538dbd>] cpufreq_add_dev+0x62d/0xae0 [<ffffffff815389b8>] ? cpufreq_add_dev+0x228/0xae0 [<ffffffff81468569>] subsys_interface_register+0x99/0xe0 [<ffffffffa014d000>] ? 0xffffffffa014cfff [<ffffffff81535d5d>] cpufreq_register_driver+0x9d/0x200 [<ffffffffa014d000>] ? 0xffffffffa014cfff [<ffffffffa014d0e9>] acpi_cpufreq_init+0xe9/0x1000 [acpi_cpufreq] [<ffffffff810002fa>] do_one_initcall+0x11a/0x170 [<ffffffff810b4b87>] load_module+0x1cf7/0x2920 [<ffffffff81322580>] ? ddebug_proc_open+0xb0/0xb0 [<ffffffff816baee0>] ? retint_restore_args+0xe/0xe [<ffffffff810b5887>] sys_init_module+0xd7/0x120 [<ffffffff816bb6d2>] system_call_fastpath+0x16/0x1b which is quite obvious, because that commit put (multiple instances of) sysfs_create_file() under rcu_read_lock()/rcu_read_unlock(), although sysfs_create_file() may cause memory to be allocated with GFP_KERNEL and that may sleep, which is not permitted in RCU read critical section. Revert the buggy commit altogether along with some changes on top of it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Don't call __cpufreq_governor() for drivers without target()Viresh Kumar2013-04-221-5/+13
| | | | | | | | | | | | | | Some cpufreq drivers implement their own governor and so don't need us to call generic governors interface via __cpufreq_governor(). Few recent commits haven't obeyed this law well and we saw some regressions. This patch is an attempt to fix the above issue. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com> Tested-by: Dirk Brandewie <dirk.brandewie@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* cpufreq: Call __cpufreq_governor() with correct policy->cpus maskViresh Kumar2013-04-111-1/+3
| | | | | | | | | | | | | | | | | | | __cpufreq_governor() must be called with a correct policy->cpus mask. In __cpufreq_remove_dev() we initially clear policy->cpus with cpumask_clear_cpu() and then call __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT). If the governor is doing some per-cpu stuff in EXIT callback, this can create uncertain behavior. Generic governors in drivers/cpufreq/ doesn't do any per-cpu stuff in EXIT callback and so we don't face any issues currently. But its better to keep the code clean, so we don't face any issues in future. Now, we call cpumask_clear_cpu() only when multiple cpus are managed by policy. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-07 23:33:42 +0200