Following call trace appeared on one of OSS servers. Interestingly, it states "inactive for 0.00s" and "pid 13033 completed after 0.00s.".
Oct 11 13:31:28 oss23 kernel: LNet: Service thread pid 13033 was inactive for 0.00s. The thread might be hung, or it might only be slow and will resume later. Dumping the stack trace for debugging purposes:
Oct 11 13:31:28 oss23 kernel: Pid: 13033, comm: ll_ost_io01_044
Oct 11 13:31:28 oss23 kernel:
Oct 11 13:31:28 oss23 kernel: Call Trace:
Oct 11 13:31:28 oss23 kernel: [<ffffffffa083dddb>] ? ptlrpc_update_export_timer+0x4b/0x560 [ptlrpc]
Oct 11 13:31:28 oss23 kernel: [<ffffffffa0844f75>] ? ptlrpc_server_handle_request+0x385/0xc00 [ptlrpc]
Oct 11 13:31:28 oss23 kernel: [<ffffffffa04cd4aa>] ? lc_watchdog_touch+0x7a/0x190 [libcfs]
Oct 11 13:31:28 oss23 kernel: [<ffffffffa083d8d9>] ? ptlrpc_wait_event+0xa9/0x2d0 [ptlrpc]
Oct 11 13:31:28 oss23 kernel: [<ffffffff81064c00>] ? default_wake_function+0x0/0x20
Oct 11 13:31:28 oss23 kernel: [<ffffffffa08476fd>] ? ptlrpc_main+0xadd/0x1770 [ptlrpc]
Oct 11 13:31:28 oss23 kernel: [<ffffffffa0846c20>] ? ptlrpc_main+0x0/0x1770 [ptlrpc]
Oct 11 13:31:28 oss23 kernel: [<ffffffff8109e78e>] ? kthread+0x9e/0xc0
Oct 11 13:31:28 oss23 kernel: [<ffffffff8100c28a>] ? child_rip+0xa/0x20
Oct 11 13:31:28 oss23 kernel: [<ffffffff8109e6f0>] ? kthread+0x0/0xc0
Oct 11 13:31:28 oss23 kernel: [<ffffffff8100c280>] ? child_rip+0x0/0x20
Oct 11 13:31:28 oss23 kernel:
Oct 11 13:31:28 oss23 kernel: LustreError: dumping log to /tmp/lustre-log.1476160288.13033
Oct 11 13:31:28 oss23 kernel: LNet: Service thread pid 13033 completed after 0.00s. This indicates the system was overloaded (too many service threads, or there were not enough hardware resources).