Commits
Michael Wang committed 2f7021a815f
cpufreq: protect 'policy->cpus' from offlining during __gov_queue_work() Jiri Kosina <jkosina@suse.cz> and Borislav Petkov <bp@alien8.de> reported the warning: [ 51.616759] ------------[ cut here ]------------ [ 51.621460] WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule+0x58/0x60() [ 51.629638] Modules linked in: ext2 vfat fat loop snd_hda_codec_hdmi usbhid snd_hda_codec_realtek coretemp kvm_intel kvm snd_hda_intel snd_hda_codec crc32_pclmul crc32c_intel ghash_clmulni_intel snd_hwdep snd_pcm aesni_intel sb_edac aes_x86_64 ehci_pci snd_page_alloc glue_helper snd_timer xhci_hcd snd iTCO_wdt iTCO_vendor_support ehci_hcd edac_core lpc_ich acpi_cpufreq lrw gf128mul ablk_helper cryptd mperf usbcore usb_common soundcore mfd_core dcdbas evdev pcspkr processor i2c_i801 button microcode [ 51.675581] CPU: 0 PID: 244 Comm: kworker/1:1 Tainted: G W 3.10.0-rc1+ #10 [ 51.683407] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 [ 51.690901] Workqueue: events od_dbs_timer [ 51.695069] 0000000000000009 ffff88043a2f5b68 ffffffff8161441c ffff88043a2f5ba8 [ 51.702602] ffffffff8103e540 0000000000000033 0000000000000001 ffff88043d5f8000 [ 51.710136] 00000000ffff0ce1 0000000000000001 ffff88044fc4fc08 ffff88043a2f5bb8 [ 51.717691] Call Trace: [ 51.720191] [<ffffffff8161441c>] dump_stack+0x19/0x1b [ 51.725396] [<ffffffff8103e540>] warn_slowpath_common+0x70/0xa0 [ 51.731473] [<ffffffff8103e58a>] warn_slowpath_null+0x1a/0x20 [ 51.737378] [<ffffffff81025628>] native_smp_send_reschedule+0x58/0x60 [ 51.744013] [<ffffffff81072cfd>] wake_up_nohz_cpu+0x2d/0xa0 [ 51.749745] [<ffffffff8104f6bf>] add_timer_on+0x8f/0x110 [ 51.755214] [<ffffffff8105f6fe>] __queue_delayed_work+0x16e/0x1a0 [ 51.761470] [<ffffffff8105f251>] ? try_to_grab_pending+0xd1/0x1a0 [ 51.767724] [<ffffffff8105f78a>] mod_delayed_work_on+0x5a/0xa0 [ 51.773719] [<ffffffff814f6b5d>] gov_queue_work+0x4d/0xc0 [ 51.779271] [<ffffffff814f60cb>] od_dbs_timer+0xcb/0x170 [ 51.784734] [<ffffffff8105e75d>] process_one_work+0x1fd/0x540 [ 51.790634] [<ffffffff8105e6f2>] ? process_one_work+0x192/0x540 [ 51.796711] [<ffffffff8105ef22>] worker_thread+0x122/0x380 [ 51.802350] [<ffffffff8105ee00>] ? rescuer_thread+0x320/0x320 [ 51.808264] [<ffffffff8106634a>] kthread+0xea/0xf0 [ 51.813200] [<ffffffff81066260>] ? flush_kthread_worker+0x150/0x150 [ 51.819644] [<ffffffff81623d5c>] ret_from_fork+0x7c/0xb0 [ 51.918165] nouveau E[ DRM] GPU lockup - switching to software fbcon [ 51.930505] [<ffffffff81066260>] ? flush_kthread_worker+0x150/0x150 [ 51.936994] ---[ end trace f419538ada83b5c5 ]--- It was caused by the policy->cpus changed during the process of __gov_queue_work(), in other word, cpu offline happened. Use get/put_online_cpus() to prevent the offline from happening while __gov_queue_work() is running. [rjw: The problem has been present since recent commit 031299b (cpufreq: governors: Avoid unnecessary per cpu timer interrupts)] References: https://lkml.org/lkml/2013/6/5/88 Reported-by: Borislav Petkov <bp@alien8.de> Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>