cpufreq_governor_dbs+0x397 または __cpufreq_governor+0x2b でカーネルがクラッシュする

Issue

• サーバーのシステムログに以下のような警告メッセージが複数記録されます。

------------[ cut here ]------------
WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xb8/0xd0() (Tainted:G        W  ---------------   )
Hardware name:ProLiant DL360p Gen8
sysfs: cannot create duplicate filename '/devices/system/cpu/cpu9/cpufreq/ondemand'
Modules linked in:... cpufreq_ondemand freq_table pcc_cpufreq ...[last unloaded: freq_table]
Pid:47469, comm: cpuspeed Tainted:G        W  ---------------    2.6.32-358.el6.x86_64 #1
Call Trace:
 [<ffffffff8106e2e7>] ? warn_slowpath_common+0x87/0xc0
 [<ffffffff8106e3d6>] ? warn_slowpath_fmt+0x46/0x50
 [<ffffffff811fb898>] ? sysfs_add_one+0xb8/0xd0
 [<ffffffff811fb918>] ? create_dir+0x68/0xb0
 [<ffffffff811fb9cb>] ? sysfs_create_subdir+0x1b/0x20
 [<ffffffff811fcd18>] ? internal_create_group+0x58/0x1a0
 [<ffffffff811fce93>] ? sysfs_create_group+0x13/0x20
 [<ffffffffa0224a13>] ? cpufreq_governor_dbs+0x163/0x470 [cpufreq_ondemand]
 [<ffffffff8112a281>] ? get_page_from_freelist+0x3d1/0x830
 [<ffffffff81414857>] ? cpufreq_governor_userspace+0x2f7/0x330
 [<ffffffff814131a9>] ?__cpufreq_governor+0xb9/0x180
 [<ffffffff8141343f>] ?__cpufreq_set_policy+0x1cf/0x250
 [<ffffffff81413954>] ? store_scaling_governor+0xe4/0x210
 [<ffffffff814135f0>] ? handle_update+0x0/0x40
 [<ffffffff8127923a>] ? kobject_get+0x1a/0x30
 [<ffffffff8150f200>] ? hrtimer_nanosleep_restart+0x20/0x90
 [<ffffffff81412a27>] ? store+0x67/0xa0
 [<ffffffff811f97c5>] ? sysfs_write_file+0xe5/0x170
 [<ffffffff81180f98>] ? vfs_write+0xb8/0x1a0
 [<ffffffff81181891>] ? sys_write+0x51/0x90
 [<ffffffff810dc565>] ?__audit_syscall_exit+0x265/0x290
 [<ffffffff8100b072>] ? system_call_fastpath+0x16/0x1b
---[ end trace 448bc8fe604185a3 ]---

• システムが "cpufreq_governor_dbs+0x397/0x470" の "divide error" によりクラッシュしている可能性があり、クラッシュダンプで以下のコールトレースが出力されます。

divide error:0000 [#1] SMP 
last sysfs file:/sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
Modules linked in:... cpufreq_ondemand freq_table pcc_cpufreq ...[last unloaded: freq_table]
Pid:48308, comm: cpuspeed Tainted:G        W  ---------------    2.6.32-358.el6.x86_64 #1 HP ProLiant DL360p Gen8
RIP:0010:[<ffffffffa037dc47>]  [<ffffffffa037dc47>] cpufreq_governor_dbs+0x397/0x470 [cpufreq_ondemand]
RSP:0018:ffff883f4eab5be8  EFLAGS:00010246
RAX:000000010017c0dc RBX:0000000000000000 RCX:0000000000000000
RDX:0000000000000000 RSI:0000000000000000 RDI: ffff880099837548
RBP: ffff883f4eab5c88 R08: ffff882012a3f008 R09:0000000000000040
R10:0000000000000001 R11:0000000000000000 R12:0000000000000001
R13: ffff880099837500 R14: ffff880099837500 R15:0000000000011400
FS:00007fdf271f6700(0000) GS:ffff880099840000(0000) knlGS:0000000000000000
CS:0010 DS:0000 ES:0000 CR0:0000000080050033
CR2:0000003dd6300040 CR3:0000003f4d95b000 CR4: 00000000000427e0
DR0:0000000000000000 DR1:0000000000000000 DR2:0000000000000000
DR3:0000000000000000 DR6:00000000ffff0ff0 DR7:0000000000000400
Process cpuspeed (pid:48308, threadinfo ffff883f4eab4000, task ffff88400ad87500)
Stack:
 ffff883f4eab5d08 ffffffff8112a281 ffff883f4eab5c18 0000000000000001
<d> 0000000000000002 000000006b4b36de 0000000000000001 ffff880099837500
<d> 0000000000011400 00000000637742f6 0000000000017500 ffff880099837510
Call Trace:
 [<ffffffff8112a281>] ? get_page_from_freelist+0x3d1/0x830
 [<ffffffff814131a9>] __cpufreq_governor+0xb9/0x180
 [<ffffffff8141343f>] __cpufreq_set_policy+0x1cf/0x250
 [<ffffffff81413954>] store_scaling_governor+0xe4/0x210
 [<ffffffff814135f0>] ? handle_update+0x0/0x40
 [<ffffffff8127923a>] ? kobject_get+0x1a/0x30
 [<ffffffff8150f200>] ? hrtimer_nanosleep_restart+0x20/0x90
 [<ffffffff81412a27>] store+0x67/0xa0
 [<ffffffff811f97c5>] sysfs_write_file+0xe5/0x170
 ...skip...

• または、システムが "__cpufreq_governor+0x2b/0x180" の "unable to handle kernel paging request" によりクラッシュしている可能性があり、クラッシュダンプに以下のコールトレースが出力されます。

BUG: unable to handle kernel paging request at ffffffffa044a788
IP:[<ffffffff8141311b>] __cpufreq_governor+0x2b/0x180
PGD 1a87067 PUD 1a8b063 PMD 40118fa067 PTE 0
Oops:0000 [#1] SMP 
last sysfs file:/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
Modules linked in:... cpufreq_ondemand freq_table pcc_cpufreq ...[last unloaded: freq_table]
Pid:29442, comm: cpuspeed Tainted:G        W  ---------------    2.6.32-358.el6.x86_64 #1 HP ProLiant DL360p Gen8
RIP:0010:[<ffffffff8141311b>]  [<ffffffff8141311b>] __cpufreq_governor+0x2b/0x180
RSP:0018:ffff881f67e1dc98  EFLAGS:00010282
RAX: ffff8800998137e0 RBX: ffff884010f50180 RCX:0000000000124f80
RDX: ffffffff00000001 RSI: ffffffffa044a760 RDI: ffff884010f50180
RBP: ffff881f67e1dcd8 R08:0000000000249f00 R09:0000000000249f00
R10:0000000000000000 R11:0000000000000246 R12:0000000000000002
R13:0000000000000000 R14: ffffffffa044a760 R15: ffff881f67e1de08
FS:00007fbf9e99b700(0000) GS:ffff880099820000(0000) knlGS:0000000000000000
CS:0010 DS:0000 ES:0000 CR0:0000000080050033
CR2: ffffffffa044a788 CR3:0000003f6fac1000 CR4:00000000000427e0
DR0:0000000000000000 DR1:0000000000000000 DR2:0000000000000000
DR3:0000000000000000 DR6:00000000ffff0ff0 DR7:0000000000000400
Process cpuspeed (pid:29442, threadinfo ffff881f67e1c000, task ffff881f56439540)
Stack:
 0000000000000009 0000000000124f80 0000000000249f00 ffff881f67e1dd28
<d> ffff884010f50180 0000000000000000 ffffffffa044a760 ffff881f67e1de08
<d> ffff881f67e1dd08 ffffffff8141341f ffff884010f50180 ffff881f67e1dd28
Call Trace:
 [<ffffffff8141341f>] __cpufreq_set_policy+0x1af/0x250
 [<ffffffff81413954>] store_scaling_governor+0xe4/0x210
 [<ffffffff814135f0>] ? handle_update+0x0/0x40
 [<ffffffff8127923a>] ? kobject_get+0x1a/0x30
 [<ffffffff8150f200>] ? hrtimer_nanosleep_restart+0x20/0x90
 [<ffffffff81412a27>] store+0x67/0xa0
 [<ffffffff811f97c5>] sysfs_write_file+0xe5/0x170
 ...skip...