INFO: task syz-executor7:7866 blocked for more than 120 seconds. Not tainted 4.4.110-gdac1439 #13 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor7 D ffff8801d9bafaa8 29288 7866 3531 0x20020004 ffff8801d9bafaa8 ffffffff851d98b0 ffff8800b3214fc8 ffff8800b3214fa0 ffff8800b3214fa8 ffff8800b3214f00 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8 ffff8800b30d8000 ffff8800b3214740 ffff8801d9ba8000 Call Trace: [] schedule+0x9a/0x1c0 kernel/sched/core.c:3351 [] schedule_timeout+0x3a1/0x970 kernel/time/timer.c:1508 [] do_wait_for_common kernel/sched/completion.c:75 [inline] [] __wait_for_common kernel/sched/completion.c:93 [inline] [] wait_for_common kernel/sched/completion.c:101 [inline] [] wait_for_completion+0x210/0x2e0 kernel/sched/completion.c:122 [] submit_bio_wait+0xf9/0x150 block/bio.c:887 [] blkdev_issue_flush+0x124/0x1e0 block/blk-flush.c:488 [] blkdev_fsync+0x85/0xb0 fs/block_dev.c:364 [] vfs_fsync_range+0x10a/0x250 fs/sync.c:195 [] vfs_fsync fs/sync.c:209 [inline] [] do_fsync+0x42/0xb0 fs/sync.c:219 [] SYSC_fdatasync fs/sync.c:233 [inline] [] SyS_fdatasync+0x19/0x20 fs/sync.c:231 [] do_syscall_32_irqs_on arch/x86/entry/common.c:390 [inline] [] do_fast_syscall_32+0x314/0x890 arch/x86/entry/common.c:457 [] sysenter_flags_fixed+0xd/0x17 no locks held by syz-executor7/7866. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.110-gdac1439 #13 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffffffff84217840 task.stack: ffffffff84200000 RIP: 0010:[] [] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49 RSP: 0018:ffffffff84207da0 EFLAGS: 00000246 RAX: 0000000000000007 RBX: ffffffff847dc2c8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff842180ac RBP: ffffffff84207da0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000000b7b8e000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff84207dd8 ffffffff81027e15 ffffffff84208000 ffffffff847dc2c8 0000000000000000 0000000000000000 dffffc0000000000 ffffffff84207de8 ffffffff8102938a ffffffff84207e00 ffffffff81220438 ffffffff84208000 Call Trace: [] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline] [] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:291 [] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:282 [] default_idle_call+0x48/0x70 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+0x605/0x820 kernel/sched/idle.c:301 [] rest_init+0x189/0x190 init/main.c:410 [] start_kernel+0x6b9/0x6ee init/main.c:682 [] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:196 [] x86_64_start_kernel+0x140/0x163 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: 486 Comm: khungtaskd Not tainted 4.4.110-gdac1439 #13 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800bac44740 task.stack: ffff8800bb2a8000 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+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69 RSP: 0018:ffff8800bb2afcb8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8800bb2afce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: ffffffff8426ea20 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe7f45d3000 CR3: 00000000b7b8e000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8426ea20 ffffffff847ee1c0 000000000001bca0 0000000000000040 dffffc0000000000 ffff8800bb2afd00 ffffffff810b94fb ffffffff839f56a0 0000000000000003 ffff8800bb2afd60 ffffffff81d0fd97 0000000000000000 Call Trace: [] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace+0x4a7/0x550 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+0x6fa/0xae0 kernel/hung_task.c:238 [] kthread+0x268/0x300 kernel/kthread.c:211 [] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:494 Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 5b 23 17 00 4c 89 e7 57 9d 0f 1f