Viresh, Got that box and did some debug, found the policy->kobj is not initialized. So the race happened between cpufreq_cpu_get() and __cpufreq_add_dev(), and verified 'this' race could be fixed by commit
6d4e81e cpufreq: Ref the policy object sooner
I have reboot the box with crond for more than 12 hours, no warning found.
But obviously, the commit cpufreq: Set cpufreq_cpu_data to NULL before putting kobject also fixed one of the possible race condition.
Thanks, Ethan
On Thu, Feb 26, 2015 at 12:31 AM, santosh shilimkar santosh.shilimkar@oracle.com wrote:
On 2/24/2015 9:47 PM, Ethan Zhao wrote:
Viresh,
Will do that when I get the test box.Thanks Ethan.
On Wed, Feb 25, 2015 at 12:35 PM, viresh kumar viresh.kumar@linaro.org wrote:
On Wednesday 25 February 2015 08:54 AM, Ethan Zhao wrote:
Viresh, With this patch applied, still got the following warning and panic, seems it needs more care.
54.474618] ------------[ cut here ]------------[ 54.545816] WARNING: CPU: 0 PID: 213 at include/linux/kref.h:47 kobject_get+0x41/0x50() [ 54.642595] Modules linked in: i2c_i801(+) mfd_core shpchp(+) acpi_cpufreq(+) edac_core ioatdma(+) xfs libcrc32c ast syscopyarea ixgbe sysfillrect sysimgblt sr_mod sd_mod drm_kms_helper igb mdio cdrom e1000e ahci dca ttm libahci uas drm i2c_algo_bit ptp megaraid_sas libata usb_storage i2c_core pps_core dm_mirror dm_region_hash dm_log dm_mod [ 55.007264] CPU: 0 PID: 213 Comm: kworker/0:2 Not tainted 3.18.5 [ 55.099970] Hardware name: Oracle Corporation SUN FIRE X4170 M2 SERVER /ASSY,MOTHERBOARD,X4170, BIOS 08120104 05/08/2012 [ 55.239736] Workqueue: kacpi_notify acpi_os_execute_deferred [ 55.308598] 0000000000000000 00000000bd730b61 ffff88046742baf8 ffffffff816b7edb [ 55.398305] 0000000000000000 0000000000000000 ffff88046742bb38 ffffffff81078ae1 [ 55.488040] ffff88046742bbd8 ffff8806706b3000 0000000000000292 0000000000000000 [ 55.577776] Call Trace: [ 55.608228] [<ffffffff816b7edb>] dump_stack+0x46/0x58 [ 55.670895] [<ffffffff81078ae1>] warn_slowpath_common+0x81/0xa0 [ 55.743952] [<ffffffff81078bfa>] warn_slowpath_null+0x1a/0x20 [ 55.814929] [<ffffffff8130d0d1>] kobject_get+0x41/0x50 [ 55.878654] [<ffffffff8153e955>] cpufreq_cpu_get+0x75/0xc0 [ 55.946528] [<ffffffff8153f37e>] cpufreq_update_policy+0x2e/0x1f0 [ 56.021682] [<ffffffff810bf9d2>] ? up+0x32/0x50 [ 56.078126] [<ffffffff813ab975>] ? acpi_ns_get_node+0xcb/0xf2 [ 56.148974] [<ffffffff813abdc9>] ? acpi_evaluate_object+0x22c/0x252 [ 56.226066] [<ffffffff813ac3c2>] ? acpi_get_handle+0x95/0xc0 [ 56.295871] [<ffffffff8138a7fb>] ? acpi_has_method+0x25/0x40 [ 56.365661] [<ffffffff813bbcd4>] acpi_processor_ppc_has_changed+0x77/0x82 [ 56.448956] [<ffffffff8108f726>] ? move_linked_works+0x66/0x90 [ 56.520842] [<ffffffff813b87b9>] acpi_processor_notify+0x58/0xe7 [ 56.594807] [<ffffffff8139dfd8>] acpi_ev_notify_dispatch+0x44/0x5c [ 56.670859] [<ffffffff81388fe3>] acpi_os_execute_deferred+0x15/0x22 [ 56.747936] [<ffffffff8109268e>] process_one_work+0x14e/0x3f0 [ 56.818766] [<ffffffff81092d9b>] worker_thread+0x11b/0x4d0 [ 56.886486] [<ffffffff81092c80>] ? rescuer_thread+0x350/0x350 [ 56.957316] [<ffffffff810984f1>] kthread+0xe1/0x100 [ 57.017742] [<ffffffff81098410>] ? kthread_create_on_node+0x1b0/0x1b0 [ 57.096903] [<ffffffff816bfe7c>] ret_from_fork+0x7c/0xb0 [ 57.162534] [<ffffffff81098410>] ? kthread_create_on_node+0x1b0/0x1b0 [ 57.241680] ---[ end trace dce06bb76f547de5 ]---
Any idea ?
No. Santosh reported this to me few days back, I asked him to perform some testing but don't know what happened after that..
I didn't get time to re-look into it so far.
Regards, Santosh