Buffer I/O error on dev loop0, logical block 3, async page read Buffer I/O error on dev loop0, logical block 1, lost async page write Buffer I/O error on dev loop0, logical block 2, lost async page write Buffer I/O error on dev loop0, logical block 3, lost async page write INFO: task syz-executor4:15842 blocked for more than 120 seconds. Not tainted 4.4.120-gd63fdf6 #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D ffff8801c60372c0 26544 15842 3855 0x00000004 ffff8801c60372c0 ffff8801c6f4e8d0 0000000000000024 ffff8801c6f4e000 ffffffff842bdbe0 0000000000000000 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8 ffffffff84217840 ffff8801c6f4e000 ffff8801c6037860 Call Trace: [] schedule+0x7a/0x1b0 kernel/sched/core.c:3353 [] schedule_timeout+0x3a0/0x970 kernel/time/timer.c:1515 [] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:4935 [] io_schedule include/linux/sched.h:447 [inline] [] bit_wait_io+0x1b/0xc0 kernel/sched/wait.c:595 [] __wait_on_bit+0x8c/0x140 kernel/sched/wait.c:395 [] wait_on_page_bit+0x1e5/0x210 mm/filemap.c:758 [] wait_on_page_writeback include/linux/pagemap.h:530 [inline] [] __filemap_fdatawait_range+0x1c3/0x2e0 mm/filemap.c:410 [] filemap_fdatawait_range+0x25/0x50 mm/filemap.c:440 [] filemap_write_and_wait_range+0x74/0xb0 mm/filemap.c:539 [] blkdev_fsync+0x66/0xb0 fs/block_dev.c:355 [] vfs_fsync_range+0x10a/0x250 fs/sync.c:195 [] generic_write_sync include/linux/fs.h:2497 [inline] [] blkdev_write_iter+0x398/0x490 fs/block_dev.c:1658 [] vfs_iter_write+0x1c7/0x2d0 fs/read_write.c:364 [] iter_file_splice_write+0x58a/0xae0 fs/splice.c:1024 [] do_splice_from fs/splice.c:1128 [inline] [] direct_splice_actor+0x125/0x180 fs/splice.c:1294 [] splice_direct_to_actor+0x2d2/0x830 fs/splice.c:1247 [] do_splice_direct+0x1a7/0x270 fs/splice.c:1337 [] do_sendfile+0x54c/0xd30 fs/read_write.c:1227 [] SYSC_sendfile64 fs/read_write.c:1282 [inline] [] SyS_sendfile64+0xc3/0x150 fs/read_write.c:1274 [] entry_SYSCALL_64_fastpath+0x1c/0x98 no locks held by syz-executor4/15842. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.120-gd63fdf6 #28 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:ffffffff84207dc0 EFLAGS: 00000246 RAX: 0000000000000007 RBX: ffffffff847ddc08 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8421810c RBP: ffffffff84207dc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: fffffbfff070889c R14: ffffffff847ebf78 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7614c52000 CR3: 00000001c7468000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff84207df8 ffffffff81027e85 ffffffff84208000 ffffffff847ddc08 fffffbfff070889c ffffffff847ebf78 0000000000000000 ffffffff84207e08 ffffffff810293fa ffffffff84207e20 ffffffff81221468 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+0xa/0x10 arch/x86/kernel/process.c:281 [] 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+0x5fd/0x8f0 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: 485 Comm: khungtaskd Not tainted 4.4.120-gd63fdf6 #28 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800baceb000 task.stack: ffff8800baca8000 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:ffff8800bacafcb8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8800bacafce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: ffffffff8426f420 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000219b9d0 CR3: 00000001c7468000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8426f420 ffffffff847efb00 fffffbfff08fda14 dffffc0000000000 ffff8801db31bca0 ffff8800bacafd00 ffffffff810b999b ffffffff839f63c0 0000000000000003 ffff8800bacafd60 ffffffff81d0eff4 0000000000000000 Call Trace: [] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 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+0x55/0x80 arch/x86/entry/entry_64.S:506 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 6b 2f 17 00 4c 89 e7 57 9d 0f 1f