INFO: task loop4:2092 blocked for more than 120 seconds. Not tainted 4.4.132-gc3c51ea #45 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. loop4 D ffff8800bb9eed40 26880 2092 2 0x00000000 ffff8800bb9eed40 ffff8800aeb7e8d8 ffff8800aeb7e900 ffff8800aeb7e8e0 1ffff1001773dd00 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8 ffff8801db31f4c0 ffff8801c83ae000 ffff8800aeb7e000 ffff8800bb9ef610 Call Trace: [] schedule+0x7a/0x1b0 kernel/sched/core.c:3359 [] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515 [] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:4941 [] io_schedule include/linux/sched.h:447 [inline] [] bt_get+0x2af/0x760 block/blk-mq-tag.c:301 [] __blk_mq_get_tag block/blk-mq-tag.c:325 [inline] [] blk_mq_get_tag+0x1f5/0x360 block/blk-mq-tag.c:353 [] __blk_mq_alloc_request+0x27/0xa40 block/blk-mq.c:215 [] blk_mq_map_request.isra.42+0x732/0xe00 block/blk-mq.c:1190 [] blk_sq_make_request+0x1ad/0xe60 block/blk-mq.c:1361 [] generic_make_request+0x211/0x9b0 block/blk-core.c:2081 [] submit_bio+0xdf/0x3b0 block/blk-core.c:2154 [] dio_bio_submit fs/direct-io.c:409 [inline] [] do_blockdev_direct_IO+0x5aab/0x82f0 fs/direct-io.c:1283 [] __blockdev_direct_IO+0xae/0xe0 fs/direct-io.c:1342 [] blkdev_direct_IO+0xb2/0xe0 fs/block_dev.c:167 [] generic_file_read_iter+0x35c/0x1150 mm/filemap.c:1790 [] blkdev_read_iter+0x105/0x170 fs/block_dev.c:1679 [] lo_rw_aio+0x481/0x870 drivers/block/loop.c:506 [] lo_rw_simple drivers/block/loop.c:520 [inline] [] do_req_filebacked drivers/block/loop.c:558 [inline] [] loop_handle_cmd drivers/block/loop.c:1705 [inline] [] loop_queue_work+0x12b7/0x1620 drivers/block/loop.c:1717 [] kthread_worker_fn+0x1c3/0x610 kernel/kthread.c:602 [] kthread+0x268/0x300 kernel/kthread.c:211 [] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510 no locks held by loop4/2092. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.132-gc3c51ea #45 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffffffff84417840 task.stack: ffffffff84400000 RIP: 0010:[] [] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49 RSP: 0018:ffffffff84407dc8 EFLAGS: 00000246 RAX: 0000000000000007 RBX: ffffffff84a05b28 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8441811c RBP: ffffffff84407dc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: fffffbfff074890c R15: ffffffff84a05b28 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c420143e80 CR3: 00000001cfc54000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff84407e00 ffffffff81025da5 ffffffff84408000 0000000000000000 0000000000000000 fffffbfff074890c ffffffff84a05b28 ffffffff84407e10 ffffffff810272f0 ffffffff84407e28 ffffffff8121b9e7 dffffc0000000000 Call Trace: [] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline] [] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:290 [] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:281 [] default_idle_call+0x57/0x70 kernel/sched/idle.c:93 [] cpuidle_idle_call kernel/sched/idle.c:157 [inline] [] cpu_idle_loop kernel/sched/idle.c:253 [inline] [] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301 [] rest_init+0x188/0x18e init/main.c:410 [] start_kernel+0x6b3/0x6e7 init/main.c:682 [] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196 [] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:185 Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 66 0f 1f 84 NMI backtrace for cpu 1 CPU: 1 PID: 491 Comm: khungtaskd Not tainted 4.4.132-gc3c51ea #45 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800bac61800 task.stack: ffff8801d9270000 RIP: 0010:[] [] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline] RIP: 0010:[] [] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline] RIP: 0010:[] [] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline] RIP: 0010:[] [] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69 RSP: 0018:ffff8801d9277cc8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8801d9277cf0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f7a0 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc9b8f92140 CR3: 00000001cfc54000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8446f7a0 ffffffff84a18a60 0000000000000007 fffffbfff0942bfc 0000000000000040 ffff8801d9277d10 ffffffff810b5dd1 ffffffff83c0b1a0 0000000000000003 ffff8801d9277d68 ffffffff81e19003 ffff8800aeb7e000 Call Trace: [] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85 [] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 [] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238 [] kthread+0x268/0x300 kernel/kthread.c:211 [] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510 Code: b3 5f ff f6 c4 10 75 e2 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 f2 09 da 80 cf 04 41 83 fe 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 75 1a 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f2