WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xb8/0xd0()
Environment
- Hitachi Compute Blade 520XB1
- Red Hat Enterprise Linux 6.5
- Red Hat Enterprise Linux 7.0
- Hitachi Compute Blade 520XB2
- Red Hat Enterprise Linux 6.6
- Red Hat Enterprise Linux 7.1
Issue
- The following warning is logged in syslog
WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xb8/0xd0()
Resolution
By disabling the use of iTCO_wdt module as below, users are able to properly run the operating system on the server.
Append following line in /etc/modprobe.d/blacklist.conf and reboot the system.
blacklist iTCO_wdt
NOTE: with above the configuration, users are ineligible to get benefits of iTCO_wdt module. In cases the server may persist to hang without iTCO_wdt module taking proper action to resolve the circumstance.
Root Cause
- The design of the server allows more than one iTCO to be exposed to the running operating system.
- Currently Intel, Hitachi, and Red Hat are collaborating so RHEL is able to handle the circumstance.
- The traceback occurs because of sysfs trying to register two files with the same name. This may trigger an unexpected reboot of the system.
Diagnostic Steps
When a box encounters this issue the following is logged in kernel syslog:
sysfs: cannot create duplicate filename '/bus/platform/devices/iTCO_wdt'
Modules linked in: lpc_ich(+) mfd_core shpchp ext4 jbd2 mbcache sd_mod crc_t10dif sr_mod cdrom megaraid_sas usb_storage xhci_hcd wmi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]
Pid: 5650, comm: work_for_cpu Not tainted 2.6.32-431.el6.x86_64 #1
Call Trace:
[<ffffffff81071e27>] ? warn_slowpath_common+0x87/0xc0
[<ffffffff81071f16>] ? warn_slowpath_fmt+0x46/0x50
[<ffffffff81205f18>] ? sysfs_add_one+0xb8/0xd0
[<ffffffff812063ab>] ? sysfs_do_create_link+0x12b/0x170
[<ffffffff81206423>] ? sysfs_create_link+0x13/0x20
[<ffffffff8136c99d>] ? bus_add_device+0xed/0x1d0
[<ffffffff8136aaee>] ? device_add+0x4ce/0x650
[<ffffffff81369821>] ? dev_set_name+0x41/0x50
[<ffffffff8136f685>] ? platform_device_add+0x125/0x200
[<ffffffffa01531c8>] ? mfd_add_devices+0x188/0x22c [mfd_core]
[<ffffffffa01572f7>] ? lpc_ich_probe+0x1e0/0x417 [lpc_ich]
[<ffffffff810951c0>] ? do_work_for_cpu+0x0/0x30
[<ffffffff812a4db7>] ? local_pci_probe+0x17/0x20
[<ffffffff810951d8>] ? do_work_for_cpu+0x18/0x30
[<ffffffff8109aef6>] ? kthread+0x96/0xa0
[<ffffffff8100c20a>] ? child_rip+0xa/0x20
[<ffffffff8109ae60>] ? kthread+0x0/0xa0
[<ffffffff8100c200>] ? child_rip+0x0/0x20
---[ end trace 9910524434959522 ]---
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