kernel.git/drivers/cpufreq/cpufreq.c, branch linux-3.17.y

cpufreq: Avoid crash in resume on SMP without OPP

2014-11-21T17:23:13Z

commit 09712f557b31838092e1f22a5f2dd131a843a3de upstream. When resuming from s2ram on an SMP system without cpufreq operating points (e.g. there's no "operating-points" property for the CPU node in DT, or the platform doesn't use DT yet), the kernel crashes when bringing CPU 1 online: Enabling non-boot CPUs ... CPU1: Booted secondary processor Unable to handle kernel NULL pointer dereference at virtual address 0000003c pgd = ee5e6b00 [0000003c] *pgd=6e579003, *pmd=6e588003, *pte=00000000 Internal error: Oops: a07 [#1] SMP ARM Modules linked in: CPU: 0 PID: 1246 Comm: s2ram Tainted: G W 3.18.0-rc3-koelsch-01614-g0377af242bb175c8-dirty #589 task: eeec5240 ti: ee704000 task.ti: ee704000 PC is at __cpufreq_add_dev.isra.24+0x24c/0x77c LR is at __cpufreq_add_dev.isra.24+0x244/0x77c pc : [] lr : [] psr: 60000153 sp : ee705d48 ip : ee705d48 fp : ee705d84 r10: c04e0450 r9 : 00000000 r8 : 00000001 r7 : c05426a8 r6 : 00000001 r5 : 00000001 r4 : 00000000 r3 : 00000000 r2 : 00000000 r1 : 20000153 r0 : c0542734 Verify that policy is not NULL before dereferencing it to fix this. Signed-off-by: Geert Uytterhoeven Fixes: 8414809c6a1e (cpufreq: Preserve policy structure across suspend/resume) Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

cpufreq: expose scaling_cur_freq sysfs file for set_policy() drivers

2014-11-14T18:10:31Z

commit c034b02e213d271b98c45c4a7b54af8f69aaac1e upstream. Currently the core does not expose scaling_cur_freq for set_policy() drivers this breaks some userspace monitoring tools. Change the core to expose this file for all drivers and if the set_policy() driver supports the get() callback use it to retrieve the current frequency. Link: https://bugzilla.kernel.org/show_bug.cgi?id=73741 Signed-off-by: Dirk Brandewie Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

cpufreq: update 'cpufreq_suspended' after stopping governors

2014-09-30T19:02:34Z

Commit 8e30444e1530 ("cpufreq: fix cpufreq suspend/resume for intel_pstate") introduced a bug where the governors wouldn't be stopped anymore for ->target{_index}() drivers during suspend. This happens because 'cpufreq_suspended' is updated before stopping the governors during suspend and due to this __cpufreq_governor() would return early due to this check: /* Don't start any governor operations if we are entering suspend */ if (cpufreq_suspended) return 0; Fixes: 8e30444e1530 ("cpufreq: fix cpufreq suspend/resume for intel_pstate") Cc: 3.15+ # 3.15+: 8e30444e1530 "cpufreq: fix cpufreq suspend/resume for intel_pstate" Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: release policy->rwsem on error

2014-09-22T12:32:43Z

While debugging a cpufreq-related hardware failure on a system I saw the following lockdep warning: ========================= [ BUG: held lock freed! ] 3.17.0-rc4+ #1 Tainted: G E ------------------------- insmod/2247 is freeing memory ffff88006e1b1400-ffff88006e1b17ff, with a lock still held there! (&policy->rwsem){+.+...}, at: [] __cpufreq_add_dev.isra.21+0x47d/0xb80 3 locks held by insmod/2247: #0: (subsys mutex#5){+.+.+.}, at: [] subsys_interface_register+0x69/0x120 #1: (cpufreq_rwsem){.+.+.+}, at: [] __cpufreq_add_dev.isra.21+0x73/0xb80 #2: (&policy->rwsem){+.+...}, at: [] __cpufreq_add_dev.isra.21+0x47d/0xb80 stack backtrace: CPU: 0 PID: 2247 Comm: insmod Tainted: G E 3.17.0-rc4+ #1 Hardware name: HP ProLiant MicroServer Gen8, BIOS J06 08/24/2013 0000000000000000 000000008f3063c4 ffff88006f87bb30 ffffffff8171b358 ffff88006bcf3750 ffff88006f87bb68 ffffffff810e09e1 ffff88006e1b1400 ffffea0001b86c00 ffffffff8156d327 ffff880073003500 0000000000000246 Call Trace: [] dump_stack+0x4d/0x66 [] debug_check_no_locks_freed+0x171/0x180 [] ? __cpufreq_add_dev.isra.21+0x427/0xb80 [] kfree+0xab/0x2b0 [] __cpufreq_add_dev.isra.21+0x427/0xb80 [] ? _raw_spin_unlock+0x27/0x40 [] ? pcc_cpufreq_do_osc+0x17f/0x17f [pcc_cpufreq] [] cpufreq_add_dev+0xe/0x10 [] subsys_interface_register+0xc1/0x120 [] cpufreq_register_driver+0x112/0x340 [] ? kfree+0xda/0x2b0 [] ? pcc_cpufreq_do_osc+0x17f/0x17f [pcc_cpufreq] [] pcc_cpufreq_init+0x4af/0xe81 [pcc_cpufreq] [] ? pcc_cpufreq_do_osc+0x17f/0x17f [pcc_cpufreq] [] do_one_initcall+0xd4/0x210 [] ? __vunmap+0xd2/0x120 [] load_module+0x1315/0x1b70 [] ? store_uevent+0x70/0x70 [] ? copy_module_from_fd.isra.44+0x129/0x180 [] SyS_finit_module+0xa6/0xd0 [] system_call_fastpath+0x16/0x1b cpufreq: __cpufreq_add_dev: ->get() failed insmod: ERROR: could not insert module pcc-cpufreq.ko: No such device The warning occurs in the __cpufreq_add_dev() code which does down_write(&policy->rwsem); ... if (cpufreq_driver->get && !cpufreq_driver->setpolicy) { policy->cur = cpufreq_driver->get(policy->cpu); if (!policy->cur) { pr_err("%s: ->get() failed\n", __func__); goto err_get_freq; } If cpufreq_driver->get(policy->cpu) returns an error we execute the code at err_get_freq, which does not up the policy->rwsem. This causes the lockdep warning. Trivial patch to up the policy->rwsem in the error path. After the patch has been applied, and an error occurs in the cpufreq_driver->get(policy->cpu) call we will now see cpufreq: __cpufreq_add_dev: ->get() failed cpufreq: __cpufreq_add_dev: ->get() failed modprobe: ERROR: could not insert 'pcc_cpufreq': No such device Fixes: 4e97b631f24c (cpufreq: Initialize governor for a new policy under policy->rwsem) Signed-off-by: Prarit Bhargava Acked-by: Viresh Kumar Cc: 3.14+ # 3.14+ Signed-off-by: Rafael J. Wysocki

cpufreq: fix cpufreq suspend/resume for intel_pstate

2014-09-22T12:23:18Z

Cpufreq core introduces cpufreq_suspended flag to let cpufreq sysfs nodes across S2RAM/S2DISK. But the flag is only set in the cpufreq_suspend() for cpufreq drivers which have target or target_index callback. This skips intel_pstate driver. This patch is to set the flag before checking target or target_index callback. Fixes: 2f0aea936360 (cpufreq: suspend governors on system suspend/hibernate) Signed-off-by: Lan Tianyu Cc: 3.15+ # 3.15+ [rjw: Subject] Signed-off-by: Rafael J. Wysocki

cpufreq: move policy kobj to update_policy_cpu()

2014-07-21T11:43:20Z

We are calling kobject_move() from two separate places currently and both these places share another routine update_policy_cpu() which is handling everything around updating policy->cpu. Moving ownership of policy->kobj also lies under the role of update_policy_cpu() routine and must be handled from there. So, Lets move kobject_move() to update_policy_cpu() and get rid of cpufreq_nominate_new_policy_cpu() as it doesn't have anything significant left. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: propagate error returned by kobject_move()

2014-07-21T11:43:20Z

We are returning -EINVAL instead of the error returned from kobject_move() when it fails. Propagate the actual error number. Also add a meaningful print when sysfs_create_link() fails. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: don't restore policy->cpus on failure to move kobj

2014-07-21T11:43:20Z

While hot-unplugging policy->cpu, we call cpufreq_nominate_new_policy_cpu() to nominate next owner of policy, i.e. policy->cpu. If we fail to move policy kobject under the new policy->cpu, we try to update policy->cpus with the old policy->cpu. This would have been required in case old-CPU is removed from policy->cpus in the first place. But its not done before calling cpufreq_nominate_new_policy_cpu(), but during the POST_DEAD notification which happens quite late in the hot-unplugging path. So, this is just some useless code hanging around, get rid of it. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: move policy kobj to policy->cpu at resume

2014-07-17T12:23:22Z

This is only relevant to implementations with multiple clusters, where clusters have separate clock lines but all CPUs within a cluster share it. Consider a dual cluster platform with 2 cores per cluster. During suspend we start hot unplugging CPUs in order 1 to 3. When CPU2 is removed, policy->kobj would be moved to CPU3 and when CPU3 goes down we wouldn't free policy or its kobj as we want to retain permissions/values/etc. Now on resume, we will get CPU2 before CPU3 and will call __cpufreq_add_dev(). We will recover the old policy and update policy->cpu from 3 to 2 from update_policy_cpu(). But the kobj is still tied to CPU3 and isn't moved to CPU2. We wouldn't create a link for CPU2, but would try that for CPU3 while bringing it online. Which will report errors as CPU3 already has kobj assigned to it. This bug got introduced with commit 42f921a, which overlooked this scenario. To fix this, lets move kobj to the new policy->cpu while bringing first CPU of a cluster back. Also do a WARN_ON() if kobject_move failed, as we would reach here only for the first CPU of a non-boot cluster. And we can't recover from this situation, if kobject_move() fails. Fixes: 42f921a6f10c (cpufreq: remove sysfs files for CPUs which failed to come back after resume) Cc: 3.13+ # 3.13+ Reported-and-tested-by: Bu Yitian Reported-by: Saravana Kannan Reviewed-by: Srivatsa S. Bhat Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: unlock when failing cpufreq_update_policy()

2014-06-18T19:52:20Z

Commit bd0fa9bb455d introduced a failure path to cpufreq_update_policy() if cpufreq_driver->get(cpu) returns NULL. However, it jumps to the 'no_policy' label, which exits without unlocking any of the locks the function acquired earlier. This causes later calls into cpufreq to hang. Fix this by creating a new 'unlock' label and jumping to that instead. Fixes: bd0fa9bb455d ("cpufreq: Return error if ->get() failed in cpufreq_update_policy()") Link: https://devtalk.nvidia.com/default/topic/751903/kernel-3-15-and-nv-drivers-337-340-failed-to-initialize-the-nvidia-kernel-module-gtx-550-ti-/ Signed-off-by: Aaron Plattner Cc: 3.15+ # 3.15+ Signed-off-by: Rafael J. Wysocki