Seen in dmesg.  next-20130128 was OK. Haven't done a bisect, but can
do so if the offender isn't obvious...

[    2.567662] netconsole: network logging started
[    2.581661] ------------[ cut here ]------------
[    2.581670] WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0x91/0xa5()
[    2.581673] Hardware name: Latitude E6500
[    2.581676] sysfs: cannot create duplicate filename '/devices/system/cpu/cpufreq/ondemand'
[    2.581678] Modules linked in:
[    2.581684] Pid: 1, comm: swapper/0 Tainted: G        W    3.8.0-rc6-next-20130206 #57
[    2.581687] Call Trace:
[    2.581693]  [<ffffffff811713d6>] ? sysfs_add_one+0x91/0xa5
[    2.581700]  [<ffffffff8102ecdc>] warn_slowpath_common+0x7c/0x96
[    2.581706]  [<ffffffff8102ed3d>] warn_slowpath_fmt+0x47/0x49
[    2.581711]  [<ffffffff811713d6>] sysfs_add_one+0x91/0xa5
[    2.581716]  [<ffffffff81171521>] create_dir+0x6b/0xa4
[    2.581721]  [<ffffffff81171787>] sysfs_create_subdir+0x17/0x19
[    2.581727]  [<ffffffff81172e76>] internal_create_group+0xd4/0x1df
[    2.581732]  [<ffffffff81172f8f>] sysfs_create_group+0xe/0x10
[    2.581739]  [<ffffffff813e033a>] cpufreq_governor_dbs+0x209/0x475
[    2.581744]  [<ffffffff813df187>] od_cpufreq_governor_dbs+0x15/0x17
[    2.581750]  [<ffffffff813dd6ab>] __cpufreq_governor+0x61/0xb5
[    2.581755]  [<ffffffff813dd803>] __cpufreq_set_policy+0x104/0x140
[    2.581761]  [<ffffffff81609303>] cpufreq_add_dev_interface+0x217/0x261
[    2.581767]  [<ffffffff813de5ed>] ? cpufreq_update_policy+0x133/0x133
[    2.581773]  [<ffffffff813dddc9>] cpufreq_add_dev+0x222/0x2d7
[    2.581780]  [<ffffffff812dc7da>] subsys_interface_register+0xa3/0xd7
[    2.581786]  [<ffffffff8160e6c9>] ? _raw_spin_unlock_irqrestore+0x72/0x80
[    2.581792]  [<ffffffff813dd1ae>] cpufreq_register_driver+0x9c/0x13b
[    2.581799]  [<ffffffff81d778ed>] ? cpufreq_gov_dbs_init+0x2c/0x2c
[    2.581805]  [<ffffffff81d77968>] acpi_cpufreq_init+0x7b/0x185
[    2.581811]  [<ffffffff8100023a>] do_one_initcall+0x7a/0x130
[    2.581817]  [<ffffffff81d4ddfb>] kernel_init_freeable+0x15e/0x1df
[    2.581822]  [<ffffffff81d4d6f2>] ? do_early_param+0x88/0x88
[    2.581828]  [<ffffffff815f9568>] ? rest_init+0x12c/0x12c
[    2.581833]  [<ffffffff815f9571>] kernel_init+0x9/0xd1
[    2.581839]  [<ffffffff81614bec>] ret_from_fork+0x7c/0xb0
[    2.581844]  [<ffffffff815f9568>] ? rest_init+0x12c/0x12c
[    2.581847] ---[ end trace a0eea8e0db3a3905 ]---
[    2.585909] ALSA device list:
[    2.585913]   #0: HDA Intel at 0xf6fdc000 irq 48
[    2.590781] Freeing unused kernel memory: 852k freed