system error at lib/kobject.c:595 kobject_put+0x50/0x60 with SCSI tape drive

Issue

• The customer is using NetVault to take backup.
• Intermittently (once per several weeks) the system gets hang with following messages logged:

kernel: ------------[ cut here ]------------
kernel: WARNING: at lib/kobject.c:595 kobject_put+0x50/0x60() (Not tainted)
kernel: Hardware name: ProLiant DL380p Gen8
kernel: kobject: '(null)' (ffff880231f15588): is not initialized, yet kobject_put() is being called.
kernel: Modules linked in: fuse mptctl mptbase autofs4 sunrpc talpa_vfshook(U) talpa_pedconnector(U) talpa_pedevice(U) talpa_vcdevice(U) talpa_core(U) talpa_linux(U) talpa_syscallhook(U) pcc_cpufreq bonding 8021q garp stp llc ipv6 power_meter hpilo hpwdt tg3 osst st ch sg microcode serio_raw iTCO_wdt iTCO_vendor_support ioatdma dca shpchp ext4 mbcache jbd2 sd_mod crc_t10dif sr_mod cdrom hpsa bfa scsi_transport_fc scsi_tgt pata_acpi ata_generic ata_piix dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]
kernel: Pid: 22, comm: events/3 Not tainted 2.6.32-279.14.1.el6.x86_64 #1
kernel: Call Trace:
kernel: [<ffffffff8106b7b7>] ? warn_slowpath_common+0x87/0xc0
kernel: [<ffffffff8106b8a6>] ? warn_slowpath_fmt+0x46/0x50
kernel: [<ffffffff812743b0>] ? kobject_put+0x50/0x60
kernel: [<ffffffff81255895>] ? blk_put_queue+0x15/0x20
kernel: [<ffffffff81371184>] ? scsi_device_dev_release_usercontext+0xd4/0x120
kernel: [<ffffffff8108cf75>] ? execute_in_process_context+0x55/0x60
kernel: [<ffffffff813710ac>] ? scsi_device_dev_release+0x1c/0x20
kernel: [<ffffffff8134c767>] ? device_release+0x27/0x90
kernel: [<ffffffff8127450d>] ? kobject_release+0x8d/0x240
kernel: [<ffffffff81274480>] ? kobject_release+0x0/0x240
kernel: [<ffffffff81275b57>] ? kref_put+0x37/0x70
kernel: [<ffffffff81274387>] ? kobject_put+0x27/0x60
kernel: [<ffffffff8134bdf7>] ? put_device+0x17/0x20
kernel: [<ffffffff81362e44>] ? scsi_device_put+0x44/0x60
kernel: [<ffffffffa013ea95>] ? sg_remove_sfp_usercontext+0x85/0xf0 [sg]
kernel: [<ffffffffa013ea10>] ? sg_remove_sfp_usercontext+0x0/0xf0 [sg]
kernel: [<ffffffff8108c800>] ? worker_thread+0x170/0x2a0
kernel: [<ffffffff81092170>] ? autoremove_wake_function+0x0/0x40
kernel: [<ffffffff8108c690>] ? worker_thread+0x0/0x2a0
kernel: [<ffffffff81091e06>] ? kthread+0x96/0xa0
kernel: [<ffffffff8100c14a>] ? child_rip+0xa/0x20
kernel: [<ffffffff81091d70>] ? kthread+0x0/0xa0
kernel: [<ffffffff8100c140>] ? child_rip+0x0/0x20
kernel: ---[ end trace 6de60c9d8ea8d2da ]---