Re: [announce] vfs-scale git tree update

From: Chris Ball
Date: Thu Jan 06 2011 - 20:00:02 EST


Hi Nick,

On Fri, Jan 07, 2011 at 11:09:53AM +1100, Nick Piggin wrote:
> > It makes the boot time of my Fedora14 on vmware much slower, while Ubuntu
> > (native, not on vmware) has no problem.
>
> Chris also noticed the problem on native hardware, so it looks like it might be
> specific to redhat.
>
> http://marc.info/?l=linux-kernel&m=129287788825563&w=2
>
> It's interesting because the rcu-walk path lookup failure even in the worst case
> that everything blows up in our face, should be a barely measurable hit -- no
> more than about 2x slowdown on something as fast as a path lookup.
>
> So I suspect it is a bug in the sysfs .d_revalidate_rcu conversion. It is a bit
> nasty and needs some cleanup anyway.
>
> So what I will do is split those conversions properly so the core code is done
> first, and the filesystem conversions done individually after that for better
> bisecting. I'll also drop the sysfs conversion (it was mainly useful for my own
> testing anyway, and not so performance critical).
>
> I might ping you again to test the sysfs patch if I get keen, after the dust of
> this merge window settles :)

I did some more digging, with Andrew's help.

In my case, the hang happens when microcode.ko is modprobed and calls
out for device firmware via request_firmware(), and then udev also calls
microcode_ctl, which attempts to open(2) /dev/cpu/microcode to write
microcode into it. (The request_firmware() interface is the preferred
one, and opening /dev/cpu/microcode is an older compatibility interface.)

During boot (but not afterwards), that open(2) on /dev/cpu/microcode
will hang in the kernel. After sixty seconds udev will declare the
helper as having failed and give up on it, and then that repeats * 8.
(I have eight CPUs). I'll attach a sysrq-w during one of the hangs.

I started to binary-search through -next and got as far as "2010-12-13
works and 2010-12-20 doesn't", but the Fedora cgroup boot failures
caused by the same vfs-scale patchset got in the way of getting closer
I'm happy to test any patches you come up with, or take suggestions for
extra debugging to do.

Thanks,

- Chris.

sysrq-w:
[ 256.977786] SysRq : Show Blocked State
[ 256.978878] task PC stack pid father
[ 256.980052] modprobe D 00000000ffff4f88 0 372 1 0x00000000
[ 256.981227] ffff88022206dc58 0000000000000086 0000000000000292 00000000ffffffff
[ 256.982415] 0000000000013840 0000000000013840 0000000000013840 ffff88022620dc40
[ 256.983692] 0000000000013840 ffff88022206dfd8 0000000000013840 0000000000013840
[ 256.984979] Call Trace:
[ 256.986306] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 256.987615] [<ffffffff8110ad4c>] ? kfree+0xc9/0xd6
[ 256.988893] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 256.990337] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 256.991637] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 256.992954] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 256.994360] [<ffffffff812f42df>] _request_firmware+0x2df/0x39a
[ 256.995688] [<ffffffff81462f2e>] ? printk+0x68/0x6a
[ 256.997079] [<ffffffff812f4424>] request_firmware+0x16/0x1a
[ 256.998430] [<ffffffffa00f6c7d>] request_microcode_fw+0x77/0x103 [microcode]
[ 256.999744] [<ffffffffa00f6358>] microcode_init_cpu+0xc4/0x115 [microcode]
[ 257.001112] [<ffffffffa00f6409>] mc_sysdev_add+0x60/0x76 [microcode]
[ 257.002458] [<ffffffff812e9772>] sysdev_driver_register+0xc0/0x11b
[ 257.003844] [<ffffffffa00d9000>] ? microcode_init+0x0/0x131 [microcode]
[ 257.005315] [<ffffffffa00d90c2>] microcode_init+0xc2/0x131 [microcode]
[ 257.006685] [<ffffffff8106db7c>] ? __blocking_notifier_call_chain+0x56/0x60
[ 257.008160] [<ffffffff8100219b>] do_one_initcall+0x7f/0x138
[ 257.009537] [<ffffffff8107fbd1>] sys_init_module+0xa6/0x1e4
[ 257.010934] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.012438] microcode_ctl D 00000000fffba41a 0 512 1 0x00000000
[ 257.013899] ffff880224c819f8 0000000000000082 ffff880224c81968 ffffffff00000000
[ 257.015430] 0000000000013840 0000000000013840 0000000000013840 ffff880222218000
[ 257.016924] 0000000000013840 ffff880224c81fd8 0000000000013840 0000000000013840
[ 257.018488] Call Trace:
[ 257.020047] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.021553] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.023148] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.024650] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.026252] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.027736] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.029244] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.030727] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.032206] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.033628] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.035156] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.036588] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.038117] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.039617] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.041149] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.042599] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.044135] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.045629] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.047179] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.048648] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.050207] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.051699] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.053287] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.054812] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.056414] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.057958] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.059552] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.061177] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.062700] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.064296] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.065835] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.067419] microcode_ctl D 00000000fffba406 0 513 1 0x00000000
[ 257.069016] ffff880224c859f8 0000000000000082 ffff880224c85968 ffffffffffffffff
[ 257.070590] 0000000000013840 0000000000013840 0000000000013840 ffff88022416dc40
[ 257.072278] 0000000000013840 ffff880224c85fd8 0000000000013840 0000000000013840
[ 257.073856] Call Trace:
[ 257.075504] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.077108] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.078701] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.080288] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.081849] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.083448] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.085030] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.086601] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.088151] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.089670] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.091256] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.092749] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.094336] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.095875] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.097461] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.099038] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.100517] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.102083] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.103592] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.105092] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.106557] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.108103] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.109543] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.111074] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.112497] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.113971] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.115423] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.116822] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.118313] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.119739] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.121195] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.122563] microcode_ctl D 00000000fffba41b 0 514 1 0x00000000
[ 257.124056] ffff8802262af9f8 0000000000000086 ffff8802262af968 ffffffff00000000
[ 257.125469] 0000000000013840 0000000000013840 0000000000013840 ffff8802243e1710
[ 257.126965] 0000000000013840 ffff8802262affd8 0000000000013840 0000000000013840
[ 257.128478] Call Trace:
[ 257.129895] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.131397] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.132816] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.134323] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.135800] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.137263] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.138719] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.140226] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.141631] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.143133] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.144541] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.146056] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.147486] [<ffffffff8121c29d>] ? kobject_get+0x1a/0x21
[ 257.149002] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.150476] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.151922] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.153424] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.154922] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.156373] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.157833] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.159353] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.160782] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.162309] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.163769] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.165290] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.166717] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.168216] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.169595] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.171077] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.172515] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.173987] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.175346] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.176721] microcode_ctl D 00000000fffba3e1 0 515 1 0x00000000
[ 257.178213] ffff880224d379f8 0000000000000082 ffff880224d37968 ffffffff00000000
[ 257.179674] 0000000000013840 0000000000013840 0000000000013840 ffff88022416ae20
[ 257.181247] 0000000000013840 ffff880224d37fd8 0000000000013840 0000000000013840
[ 257.182719] Call Trace:
[ 257.184215] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.185620] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.187110] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.188578] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.190091] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.191503] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.193012] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.194481] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.195907] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.197359] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.198767] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.200284] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.201761] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.203260] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.204698] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.206221] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.207682] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.209194] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.210624] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.212118] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.213593] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.215113] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.216536] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.218049] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.219518] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.221025] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.222420] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.223884] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.225333] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.226702] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.228167] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.229572] microcode_ctl D 00000000fffca464 0 530 1 0x00000000
[ 257.231051] ffff8802235639f8 0000000000000086 ffff880223563968 ffffffff00000000
[ 257.232464] 0000000000013840 0000000000013840 0000000000013840 ffff880224ddae20
[ 257.233979] 0000000000013840 ffff880223563fd8 0000000000013840 0000000000013840
[ 257.235443] Call Trace:
[ 257.236928] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.238349] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.239823] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.241332] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.242747] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.244269] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.245732] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.247234] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.248654] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.250156] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.251608] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.253129] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.254555] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.256083] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.257549] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.259076] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.260505] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.262027] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.263451] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.264970] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.266398] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.267973] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.269450] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.270975] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.272433] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.273945] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.275356] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.276793] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.278260] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.279644] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.281112] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.282510] microcode_ctl D 00000000fffd7a87 0 536 138 0x00000000
[ 257.283990] ffff880224e079f8 0000000000000086 ffff880224e07968 ffffffff00000000
[ 257.285427] 0000000000013840 0000000000013840 0000000000013840 ffff880224ddc530
[ 257.286938] 0000000000013840 ffff880224e07fd8 0000000000013840 0000000000013840
[ 257.288420] Call Trace:
[ 257.289929] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.291357] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.292782] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.294283] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.295709] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.297231] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.298645] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.300123] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.301589] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.303080] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.304539] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.306049] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.307480] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.309006] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.310475] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.312000] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.313426] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.314938] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.316404] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.317863] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.319340] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.320860] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.322318] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.323734] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.325249] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.326677] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.328167] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.329619] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.331064] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.332481] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.333935] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.335300] microcode_ctl D 00000000fffe80e4 0 647 162 0x00000000
[ 257.336723] ffff880222bf39f8 0000000000000082 ffff880222bf3968 ffffffff00000000
[ 257.338216] 0000000000013840 0000000000013840 0000000000013840 ffff880222b20000
[ 257.339644] 0000000000013840 ffff880222bf3fd8 0000000000013840 0000000000013840
[ 257.341171] Call Trace:
[ 257.342613] [<ffffffff81463a41>] schedule_timeout+0x36/0xe3
[ 257.344088] [<ffffffff810475a8>] ? wake_up_process+0x15/0x17
[ 257.345553] [<ffffffff81063a0e>] ? wake_up_worker+0x24/0x26
[ 257.347075] [<ffffffff81063b99>] ? insert_work+0x54/0x5c
[ 257.348539] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.350001] [<ffffffff81463824>] wait_for_common+0xad/0x102
[ 257.351412] [<ffffffff8104757f>] ? default_wake_function+0x0/0x14
[ 257.352927] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.354374] [<ffffffff812ba40c>] ? misc_open+0xab/0x197
[ 257.355868] [<ffffffff81463931>] wait_for_completion+0x1d/0x1f
[ 257.357280] [<ffffffff81062b25>] call_usermodehelper_exec+0x87/0xd6
[ 257.358799] [<ffffffff81062db6>] __request_module+0x1ba/0x1f1
[ 257.360265] [<ffffffff8103d243>] ? need_resched+0x23/0x2d
[ 257.361767] [<ffffffff812ba40c>] misc_open+0xab/0x197
[ 257.363201] [<ffffffff81119f14>] chrdev_open+0x11b/0x144
[ 257.364623] [<ffffffff81119df9>] ? chrdev_open+0x0/0x144
[ 257.366125] [<ffffffff811150f1>] __dentry_open+0x161/0x283
[ 257.367556] [<ffffffff81464cde>] ? _raw_spin_lock+0xe/0x10
[ 257.369055] [<ffffffff8112d89c>] ? mntget+0x20/0x26
[ 257.370487] [<ffffffff81115ea5>] nameidata_to_filp+0x55/0x5c
[ 257.371960] [<ffffffff8112206f>] finish_open+0xa2/0x1a4
[ 257.373444] [<ffffffff81121177>] ? do_path_lookup+0xed/0x118
[ 257.374967] [<ffffffff81122615>] do_filp_open+0x1a5/0x6db
[ 257.376430] [<ffffffff81143891>] ? fsnotify+0x23f/0x26b
[ 257.377939] [<ffffffff81463763>] ? _cond_resched+0xe/0x22
[ 257.379375] [<ffffffff81224270>] ? might_fault+0x21/0x23
[ 257.380891] [<ffffffff81224370>] ? __strncpy_from_user+0x1f/0x4e
[ 257.382329] [<ffffffff8112c4d0>] ? alloc_fd+0x74/0x11f
[ 257.383821] [<ffffffff81115f0c>] do_sys_open+0x60/0xf2
[ 257.385220] [<ffffffff81115fbe>] sys_open+0x20/0x22
[ 257.386666] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
[ 257.388128] modprobe D 00000000fffe8374 0 690 670 0x00000080
[ 257.389538] ffff880226373dc8 0000000000000086 0000000000000001 0000000000000000
[ 257.391068] 0000000000013840 0000000000013840 0000000000013840 ffff88022417dc40
[ 257.392538] 0000000000013840 ffff880226373fd8 0000000000013840 0000000000013840
[ 257.394072] Call Trace:
[ 257.395497] [<ffffffff81463ffd>] __mutex_lock_common.clone.5+0x12f/0x196
[ 257.397019] [<ffffffff81464077>] __mutex_lock_slowpath+0x13/0x15
[ 257.398461] [<ffffffff81463eb4>] mutex_lock+0x36/0x50
[ 257.399997] [<ffffffff812e972d>] sysdev_driver_register+0x7b/0x11b
[ 257.401475] [<ffffffff813a136f>] cpufreq_register_driver+0xcb/0x1b8
[ 257.403017] [<ffffffffa00e10eb>] acpi_cpufreq_init+0xeb/0x11e [acpi_cpufreq]
[ 257.404511] [<ffffffffa00e1000>] ? acpi_cpufreq_init+0x0/0x11e [acpi_cpufreq]
[ 257.406004] [<ffffffff8100219b>] do_one_initcall+0x7f/0x138
[ 257.407503] [<ffffffff8107fbd1>] sys_init_module+0xa6/0x1e4
[ 257.409020] [<ffffffff81009c02>] system_call_fastpath+0x16/0x1b
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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