INFO: task syz-executor4:12285 blocked for more than 120 seconds. Not tainted 4.4.105-g36205b7 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D ffff8801d2a275c8 27544 12285 3540 0x00000004 ffff8801d2a275c8 ffff8800b83fe790 ffff8800b83fe770 000000000000002a 0000000000005730 0000000041b58a00 ffff8801db41f838 ffff8801db41f860 ffff8801db41ef58 ffff8801d77a0000 ffff8800b83fdf00 ffff8801d2a20000 Call Trace: [] schedule+0x9a/0x1c0 kernel/sched/core.c:3351 [] schedule_timeout+0x3fc/0xb80 kernel/time/timer.c:1508 [] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:4932 [] io_schedule include/linux/sched.h:446 [inline] [] dio_await_one fs/direct-io.c:449 [inline] [] dio_await_completion fs/direct-io.c:503 [inline] [] do_blockdev_direct_IO+0x3f33/0x8150 fs/direct-io.c:1313 [] __blockdev_direct_IO+0x83/0xf0 fs/direct-io.c:1342 [] blkdev_direct_IO+0xa7/0x100 fs/block_dev.c:167 [] generic_file_read_iter+0x343/0x12d0 mm/filemap.c:1791 [] blkdev_read_iter+0xed/0x170 fs/block_dev.c:1679 [] new_sync_read fs/read_write.c:422 [inline] [] __vfs_read+0x29e/0x3e0 fs/read_write.c:434 [] vfs_read+0xe1/0x340 fs/read_write.c:454 [] SYSC_read fs/read_write.c:569 [inline] [] SyS_read+0xd3/0x1c0 fs/read_write.c:562 [] entry_SYSCALL_64_fastpath+0x16/0x76 no locks held by syz-executor4/12285. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.105-g36205b7 #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffffffff84214840 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: ffffffff847d54c8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff842150ac RBP: ffffffff84207da0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c422a62a38 CR3: 00000000b8230000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff84207dd8 ffffffff81026f25 ffffffff84208000 ffffffff847d54c8 0000000000000000 0000000000000000 dffffc0000000000 ffffffff84207de8 ffffffff8102849a ffffffff84207e00 ffffffff81214c18 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+0x152/0x160 init/main.c:409 [] start_kernel+0x638/0x66d init/main.c:680 [] 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: 484 Comm: khungtaskd Not tainted 4.4.105-g36205b7 #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d9de4740 task.stack: ffff8801d9f30000 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:ffff8801d9f37cb8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8801d9f37ce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: ffffffff8426ace0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffda9d6ac00 CR3: 00000000b8230000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8426ace0 ffffffff847e73c0 ffffffff847e4964 0000000000000001 dffffc0000000000 ffff8801d9f37d00 ffffffff810b62ab fffffbfff08fc92c 0000000000019460 ffff8801d9f37d68 ffffffff81cd3e78 0000000000000000 Call Trace: [] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace+0x428/0x590 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+0x636/0xa20 kernel/hung_task.c:238 [] kthread+0x245/0x310 kernel/kthread.c:211 [] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468 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 8b 9d 16 00 4c 89 e7 57 9d 0f 1f