Buffer I/O error on dev loop0, logical block 16, async page read INFO: task syz-executor2:18734 blocked for more than 120 seconds. Not tainted 4.4.114-ga81d322 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D ffff8800b571f550 28808 18734 3954 0x00000004 ffff8800b571f550 ffff8800b571f540 ffffffff81dac9b3 ffffffff812eb3a3 ffff8800b5a28000 00007fc812134c00 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8 ffff8801d0cb3000 ffff8800b5a28000 ffff8800b571fb40 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_lock+0x8f/0x140 kernel/sched/wait.c:434 [] __lock_page+0x18d/0x1f0 mm/filemap.c:888 [] lock_page include/linux/pagemap.h:458 [inline] [] pagecache_get_page+0x316/0x3f0 mm/filemap.c:1161 [] grab_cache_page_write_begin+0x63/0x90 mm/filemap.c:2494 [] block_write_begin+0x3a/0xd0 fs/buffer.c:2038 [] blkdev_write_begin+0x3c/0x50 fs/block_dev.c:316 [] generic_perform_write+0x28a/0x530 mm/filemap.c:2550 [] __generic_file_write_iter+0x35a/0x580 mm/filemap.c:2675 [] blkdev_write_iter+0x1d4/0x490 fs/block_dev.c:1655 [] do_iter_readv_writev+0x138/0x1e0 fs/read_write.c:664 [] do_readv_writev+0x2d2/0x6e0 fs/read_write.c:808 [] vfs_writev+0x7b/0xb0 fs/read_write.c:847 [] SYSC_pwritev fs/read_write.c:936 [inline] [] SyS_pwritev+0x199/0x230 fs/read_write.c:922 [] entry_SYSCALL_64_fastpath+0x1c/0x98 no locks held by syz-executor2/18734. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 485 Comm: khungtaskd Not tainted 4.4.114-ga81d322 #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800bace9800 task.stack: ffff8800bacf0000 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:ffff8800bacf7cb8 EFLAGS: 00000046 RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300 RBP: ffff8800bacf7ce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000003 R14: ffffffff8426f3a0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6e168f3000 CR3: 00000001cde38000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8426f3a0 ffffffff847ef700 fffffbfff08fd994 dffffc0000000000 ffff8801db31bca0 ffff8800bacf7d00 ffffffff810b988b ffffffff839f6180 0000000000000003 ffff8800bacf7d60 ffffffff81d0e8b4 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 30 17 00 4c 89 e7 57 9d 0f 1f NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.114-ga81d322 #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d9b49800 task.stack: ffff8801d9b58000 RIP: 0010:[] [] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49 RSP: 0018:ffff8801d9b5fd98 EFLAGS: 00000246 RAX: 0000000000000007 RBX: ffffffff847dd808 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801d9b4a0cc RBP: ffff8801d9b5fd98 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: fffffbfff070887c R14: ffffffff847ebb78 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6e154d6140 CR3: 00000001cde38000 CR4: 0000000000160670 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801d9b5fdd0 ffffffff81027ed5 ffff8801d9b60000 ffffffff847dd808 fffffbfff070887c ffffffff847ebb78 0000000000000000 ffff8801d9b5fde0 ffffffff8102945a ffff8801d9b5fdf8 ffffffff81221458 dffffc0000000000 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+0x5fd/0x8f0 kernel/sched/idle.c:301 [] start_secondary+0x304/0x3e0 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