Davoud Teimouri - Virtualization & Datacenter

A technology blog mainly focusing on virtualization and datacenter

Tag: Linux

kernel: WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0xbb/0xe0 – Oracle Enterprise Linux

Most of modern servers hardware are using UEFI instead of legacy BIOS and modern OS has dedicated partition to stores boot and EFI values.

Some times, the partition gets full or OS generate the below log:

kernel: WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0xbb/0xe0

Kernel includes a CONFIG_EFI_VARS_PSTORE feature, and a feature that dumps kernel message log (= the “dmesg” command output) into UEFI variables for persistent storage if the system is crashing (or even if the system is working normally, depending on the options chosen).

The cause of the warning is duplicate dump file in EFI partition and OS is trying to write values on same file.

There is a simple solution, remove old dump file!

I hope this article help you to find out root cause of the warning and resolve that.

Here is the complete log on our virtual machine:

kernel: WARNING: at lib/kobject.c:196 kobject_add_internal+0x205/0x260()
kernel: Hardware name: VMware7,1
kernel: kobject_add_internal failed for dump-type2-0-0-1493749396-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 with -EEXIST, don’t try to register things with the same name in the same directory.
kernel: Modules linked in: vmw_vsock_vmci_transport vsock oracleasm autofs4 ipv6 vfat fat uinput vmw_balloon coretemp crc32c_intel ghash_clmulni_intel microcode pcspkr sg ixgbe hwmon dca vmw_vmci i2c_piix4 shpchp ext4 jbd2 mbcache dm_round_robin scsi_dh_emc sd_mod crc_t10dif sr_mod cdrom aesni_intel ablk_helper cryptd lrw aes_x86_64 xts gf128mul vmxnet3 qla2xxx scsi_transport_fc scsi_tgt mptspi mptscsih mptbase scsi_transport_spi pata_acpi ata_generic ata_piix vmwgfx ttm drm i2c_core dm_multipath dm_mirror dm_region_hash dm_log dm_mod scsi_dh_alua [last unloaded: speedstep_lib] kernel: Pid: 5934, comm: kworker/60:2 Tainted: G        W    3.8.13-16.2.1.el6uek.x86_64 #1
kernel: Call Trace:
kernel: [<ffffffff8105d2af>] warn_slowpath_common+0x7f/0xc0
kernel: [<ffffffff8105d3a6>] warn_slowpath_fmt+0x46/0x50
kernel: [<ffffffff81286865>] kobject_add_internal+0x205/0x260
kernel: [<ffffffff81286a78>] kobject_add_varg+0x38/0x60
kernel: [<ffffffff81286af3>] kobject_init_and_add+0x53/0x70
kernel: [<ffffffff8128f140>] ? sprintf+0x40/0x50
kernel: [<ffffffff814755ec>] efivar_create_sysfs_entry+0x12c/0x1b0
kernel: [<ffffffff81475b95>] efi_pstore_write+0x1b5/0x200
kernel: [<ffffffff81214b48>] pstore_console_write+0xd8/0x100
kernel: [<ffffffff8105e027>] ? msg_print_text+0xc7/0x1e0
kernel: [<ffffffff8105f063>] call_console_drivers.clone.3+0xa3/0x100
kernel: [<ffffffff8105f4c4>] console_unlock+0x274/0x2c0
kernel: [<ffffffff8105fa75>] vprintk_emit+0x325/0x520
kernel: [<ffffffff8109e5f6>] ? find_busiest_group+0x36/0x4d0
kernel: [<ffffffff8138a189>] dev_vprintk_emit+0x69/0x90
kernel: [<ffffffff8109ebbe>] ? load_balance+0x12e/0x670
kernel: [<ffffffff8138a1e9>] dev_printk_emit+0x39/0x40
kernel: [<ffffffff81079e6f>] ? insert_work+0x3f/0x60
kernel: [<ffffffff8138a22e>] __dev_printk+0x3e/0x90
kernel: [<ffffffff8138a565>] dev_printk+0x45/0x50
kernel: [<ffffffff81048099>] ? default_spin_lock_flags+0x9/0x10
kernel: [<ffffffffa0116939>] fc_timeout_deleted_rport+0x229/0x350 [scsi_transport_fc] kernel: [<ffffffff8107b6f0>] process_one_work+0x180/0x410
kernel: [<ffffffff8107d71e>] worker_thread+0x12e/0x390
kernel: [<ffffffff8107d5f0>] ? manage_workers+0x180/0x180
kernel: [<ffffffff81082a6e>] kthread+0xce/0xe0
kernel: [<ffffffff810829a0>] ? kthread_freezable_should_stop+0x70/0x70
kernel: [<ffffffff8159b66c>] ret_from_fork+0x7c/0xb0
kernel: [<ffffffff810829a0>] ? kthread_freezable_should_stop+0x70/0x70
kernel: —[ end trace 940656e1b6e55a3d ]—

OS information:

OEL 6.5 and kernel is 3.8.13-16.2.1.el6uek.x86_64

Davoud Teimouri is as a professional blogger, vExpert 2015-2016-2017, VCA, MCITP. This blog is started with simple posts and now, it has large following readers.

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New Release – Kali Linux 2017.1

Kali Linux is one of most popular Linux distributions and many security experts are using this distribution as penetration testing system. Kali Linux is a Debian based distribution and most Kali’s packages are imported from Debian repositories.

Kali has more than 300 preinstalled tools for penetration testing such as Armitage (a graphical cyber attack management tool), nmap (a port scanner), Wireshark (a packet analyzer), John the Ripper password cracker, Aircrack-ng (a software suite for penetration-testing wireless LANs), Burp suite and OWASP ZAP web application security scanners.

Kali development team has released new version and it’s available for download.

Kali Linux

Kali Linux is available for both 32-bit and 64-bit platforms and also the team focus on ARM devices and also there is an image for ARM architecture.

Also Kali Linux NetHunter is also available for smartphones such as the Nexus 5, Nexus 6, Nexus 7, Nexus 9, Nexus 10, OnePlus One, and some Samsung Galaxy models.

Kali Linux hardware requirements:

  • A minimum of 20 GB disk space for the Kali Linux install.
  • RAM for i386 and amd64 architectures, minimum: 1GB, recommended: 2GB or more.
  • CD-DVD Drive / USB boot support

Kali Linux will be installed on some Apple devices such as Apple MacBook Air, Pro, and Retina models.

Also it will be installed on virtual platforms such as VMware Workstation and Oracle VirtualBox

Read more information on Kali Linux documentation.

Davoud Teimouri is as a professional blogger, vExpert 2015-2016-2017, VCA, MCITP. This blog is started with simple posts and now, it has large following readers.

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