INFO: task syz-executor0:7457 blocked for more than 120 seconds. Not tainted 4.4.137-ga2e2217 #59 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D ffff8801d448f460 26304 7457 3885 0x20020004 ffff8801d448f460 0000000000000040 ffff8801d3fd50d8 bbe70fed48249f99 ffff8801d448f600 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8 ffff8801db21f4c0 ffff8801d3fd0000 ffff8801d3fd4800 0000000000000000 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] [] bit_wait_io+0x1b/0xd0 kernel/sched/wait.c:595 [] __wait_on_bit_lock.part.4+0x92/0x140 kernel/sched/wait.c:434 [] __wait_on_bit_lock+0x9/0x10 kernel/sched/wait.c:427 [] __lock_page+0x17d/0x1f0 mm/filemap.c:888 [] lock_page include/linux/pagemap.h:458 [inline] [] __generic_file_splice_read+0x7eb/0xbb0 fs/splice.c:412 [] generic_file_splice_read+0xe2/0x1c0 fs/splice.c:542 [] do_splice_to+0xf7/0x140 fs/splice.c:1154 [] splice_direct_to_actor+0x242/0x830 fs/splice.c:1226 [] do_splice_direct+0x1a3/0x270 fs/splice.c:1337 [] do_sendfile+0x4e4/0xb80 fs/read_write.c:1227 [] C_SYSC_sendfile fs/read_write.c:1303 [inline] [] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1292 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 1 lock held by syz-executor0/7457: #0: (sb_writers#5){.+.+.+}, at: [] file_start_write include/linux/fs.h:2541 [inline] #0: (sb_writers#5){.+.+.+}, at: [] do_sendfile+0x863/0xb80 fs/read_write.c:1226 Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 491 Comm: khungtaskd Not tainted 4.4.137-ga2e2217 #59 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800bbb8c800 task.stack: ffff8801d8dd8000 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:ffff8801d8ddfcc8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8801d8ddfcf0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f7a0 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efd7c27e310 CR3: 00000000b2453000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8446f7a0 ffffffff84a18ee0 0000000000000007 fffffbfff0942c8c 0000000000000040 ffff8801d8ddfd10 ffffffff810b5e71 ffffffff83c0b560 0000000000000003 ffff8801d8ddfd68 ffffffff81e19e83 ffffffff8140dd6f 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 72 NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.137-ga2e2217 #59 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d9a41800 task.stack: ffff8801d9a50000 RIP: 0010:[] [] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49 RSP: 0018:ffff8801d9a57da0 EFLAGS: 00000246 RAX: 0000000000000007 RBX: ffffffff84a05fa8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801d9a420dc RBP: ffff8801d9a57da0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: fffffbfff074890c R15: ffffffff84a05fa8 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efd7c183000 CR3: 00000000b2453000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801d9a57dd8 ffffffff81025da5 ffff8801d9a58000 0000000000000000 0000000000000000 fffffbfff074890c ffffffff84a05fa8 ffff8801d9a57de8 ffffffff810272f0 ffff8801d9a57e00 ffffffff8121bc07 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 [] start_secondary+0x324/0x400 arch/x86/kernel/smpboot.c:242 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