I guess this is related? kworker 100% [Mon Dec 2 13:05:27 2019] SysRq : Show backtrace of all active CPUs [Mon Dec 2 13:05:27 2019] sending NMI to all CPUs: [Mon Dec 2 13:05:27 2019] NMI backtrace for cpu 0 skipped: idling at pc 0xffffffffb0581e94 [Mon Dec 2 13:05:27 2019] NMI backtrace for cpu 1 skipped: idling at pc 0xffffffffb0581e94 [Mon Dec 2 13:05:27 2019] NMI backtrace for cpu 2 skipped: idling at pc 0xffffffffb0581e94 [Mon Dec 2 13:05:27 2019] NMI backtrace for cpu 3 skipped: idling at pc 0xffffffffb0581e94 [Mon Dec 2 13:05:27 2019] NMI backtrace for cpu 4 [Mon Dec 2 13:05:27 2019] CPU: 4 PID: 426200 Comm: kworker/4:2 Not tainted 3.10.0-1062.4.3.el7.x86_64 #1 [Mon Dec 2 13:05:27 2019] Hardware name: Supermicro X9DRi-LN4+/X9DR3-LN4+/X9DRi-LN4+/X9DR3-LN4+, BIOS 3.0b 05/27/2014 [Mon Dec 2 13:05:27 2019] Workqueue: ceph-msgr ceph_con_workfn [libceph] [Mon Dec 2 13:05:27 2019] task: ffffa0c8e1240000 ti: ffffa0ccb6364000 task.ti: ffffa0ccb6364000 [Mon Dec 2 13:05:27 2019] RIP: 0010:[<ffffffffc08d7db9>] [<ffffffffc08d7db9>] cmpu64_rev+0x19/0x20 [ceph] [Mon Dec 2 13:05:27 2019] RSP: 0018:ffffa0ccb6367a20 EFLAGS: 00000202 [Mon Dec 2 13:05:27 2019] RAX: 0000000000000001 RBX: 0000000000000038 RCX: 0000000000000008 [Mon Dec 2 13:05:27 2019] RDX: 0000000000025c33 RSI: ffffa0cbbe380050 RDI: ffffa0cbbe380030 [Mon Dec 2 13:05:27 2019] RBP: ffffa0ccb6367a20 R08: 0000000000000018 R09: 00000000000013ed [Mon Dec 2 13:05:27 2019] R10: 0000000000000002 R11: ffffe94994f8e000 R12: ffffa0cbbe380030 [Mon Dec 2 13:05:27 2019] R13: ffffffffc08d7da0 R14: ffffa0cbbe380018 R15: ffffa0cbbe380050 [Mon Dec 2 13:05:27 2019] FS: 0000000000000000(0000) GS:ffffa0d2cfb00000(0000) knlGS:0000000000000000 [Mon Dec 2 13:05:27 2019] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [Mon Dec 2 13:05:27 2019] CR2: 000055a7c413fcb9 CR3: 0000001813010000 CR4: 00000000000607e0 [Mon Dec 2 13:05:27 2019] Call Trace: [Mon Dec 2 13:05:27 2019] [<ffffffffb019303f>] sort+0x1af/0x260 [Mon Dec 2 13:05:27 2019] [<ffffffffb0192e60>] ? u32_swap+0x10/0x10 [Mon Dec 2 13:05:27 2019] [<ffffffffc08d807b>] build_snap_context+0x12b/0x290 [ceph] [Mon Dec 2 13:05:27 2019] [<ffffffffc08d820c>] rebuild_snap_realms+0x2c/0x90 [ceph] [Mon Dec 2 13:05:27 2019] [<ffffffffc08d822b>] rebuild_snap_realms+0x4b/0x90 [ceph] [Mon Dec 2 13:05:27 2019] [<ffffffffc08d91fc>] ceph_update_snap_trace+0x3ec/0x530 [ceph] [Mon Dec 2 13:05:27 2019] [<ffffffffc08e2239>] handle_reply+0x359/0xc60 [ceph] [Mon Dec 2 13:05:27 2019] [<ffffffffc08e48ba>] dispatch+0x11a/0xb00 [ceph] [Mon Dec 2 13:05:27 2019] [<ffffffffb042e56a>] ? kernel_recvmsg+0x3a/0x50 [Mon Dec 2 13:05:27 2019] [<ffffffffc05fcff4>] try_read+0x544/0x1300 [libceph] [Mon Dec 2 13:05:27 2019] [<ffffffffafee13ce>] ? account_entity_dequeue+0xae/0xd0 [Mon Dec 2 13:05:27 2019] [<ffffffffafee4d5c>] ? dequeue_entity+0x11c/0x5e0 [Mon Dec 2 13:05:27 2019] [<ffffffffb042e417>] ? kernel_sendmsg+0x37/0x50 [Mon Dec 2 13:05:27 2019] [<ffffffffc05fdfb4>] ceph_con_workfn+0xe4/0x1530 [libceph] [Mon Dec 2 13:05:27 2019] [<ffffffffb057f568>] ? __schedule+0x448/0x9c0 [Mon Dec 2 13:05:27 2019] [<ffffffffafebe21f>] process_one_work+0x17f/0x440 [Mon Dec 2 13:05:27 2019] [<ffffffffafebf336>] worker_thread+0x126/0x3c0 [Mon Dec 2 13:05:27 2019] [<ffffffffafebf210>] ? manage_workers.isra.26+0x2a0/0x2a0 [Mon Dec 2 13:05:27 2019] [<ffffffffafec61f1>] kthread+0xd1/0xe0 [Mon Dec 2 13:05:27 2019] [<ffffffffafec6120>] ? insert_kthread_work+0x40/0x40 [Mon Dec 2 13:05:27 2019] [<ffffffffb058cd37>] ret_from_fork_nospec_begin+0x21/0x21 [Mon Dec 2 13:05:27 2019] [<ffffffffafec6120>] ? insert_kthread_work+0x40/0x40 [Mon Dec 2 13:05:27 2019] Code: 87 c8 fc ff ff 5d 0f 94 c0 0f b6 c0 c3 0f 1f 44 00 00 66 66 66 66 90 48 8b 16 48 39 17 b8 01 00 00 00 55 48 89 e5 72 08 0f 97 c0 <0f> b6 c0 f7 d8 5d c3 66 66 66 66 90 55 f6 05 ed 92 02 00 04 48 [Mon Dec 2 13:05:27 2019] NMI backtrace for cpu 5