INFO: task syz-executor.4:4663 blocked for more than 140 seconds. Not tainted 4.4.174+ #17 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D ffff8800b37a7b10 30048 4663 4658 0x20020000 ffff8800b37a7b10 ffffffff811ff385 0000000000000292 ffffffff840b1908 ffff8800b37a7ac0 0000000000000200 ffff8801db61f180 ffff8801db61f1a8 ffff8801db61e898 ffff8801cd7c2f80 ffff8801cd7c4740 ffffed00166f4001 Call Trace: [] schedule+0x99/0x1d0 kernel/sched/core.c:3355 [] schedule_timeout+0x47b/0x7c0 kernel/time/timer.c:1515 [] do_wait_for_common kernel/sched/completion.c:75 [inline] [] __wait_for_common kernel/sched/completion.c:93 [inline] [] wait_for_common+0x2b5/0x530 kernel/sched/completion.c:101 [] wait_for_completion+0x18/0x20 kernel/sched/completion.c:122 [] SYSC_io_destroy fs/aio.c:1396 [inline] [] SyS_io_destroy+0x2c1/0x350 fs/aio.c:1374 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a no locks held by syz-executor.4/4663. Sending NMI to all CPUs: NMI backtrace for cpu 0 CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #17 task: ffff8801da6f4740 task.stack: ffff8800001d0000 RIP: 0010:[] [] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline] RIP: 0010:[] [] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69 RSP: 0018:ffff8800001d7c88 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000 RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300 RBP: ffff8800001d7cb8 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000f77c9168 CR3: 00000000b4ab6000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34 000000000001b6c0 0000000000000008 ffff8800001d7cd8 ffffffff81092bee 0000000000000008 ffffffff82924260 ffff8800001d7d30 ffffffff81ab8252 Call Trace: [] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33 [] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae 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+0xd3/0xee kernel/hung_task.c:238 [] kthread+0x273/0x310 kernel/kthread.c:211 [] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537 Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1 NMI backtrace for cpu 1 CPU: 1 PID: 1926 Comm: rsyslogd Not tainted 4.4.174+ #17 task: ffff8801d69a5f00 task.stack: ffff8800b9390000 RIP: 0010:[] [] __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:100 RSP: 0018:ffff8800b9397810 EFLAGS: 00000046 RAX: ffff8801d69a5f00 RBX: ffff8801d85ffa85 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff81ad2209 RDI: ffffffff82925936 RBP: ffff8800b9397810 R08: 000000000000000a R09: 0000000000000005 R10: ffffed003b0bff50 R11: ffff8801d85ffa83 R12: 0000000000000004 R13: ffff8801d85ffa85 R14: 0000000000000000 R15: 00000000fffffffe FS: 00007f1280882700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000008148008 CR3: 00000001d7d1d000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8800b9397920 ffffffff81ad2209 ffffffff81012bc3 ffff8800b9397860 ffff8800b9397868 ffffffff81aca3ed 1ffff10017272f0f 00000004003979a8 0a000001003978f8 0000000000000462 ffffffff00000003 fffffffe00000000 Call Trace: [] number.isra.0+0x409/0x9a0 lib/vsprintf.c:460 [] vsnprintf+0x245/0x18a0 lib/vsprintf.c:1970 [] sprintf+0xc0/0x100 lib/vsprintf.c:2106 [] print_time kernel/printk/printk.c:1061 [inline] [] print_time kernel/printk/printk.c:1049 [inline] [] print_prefix+0x28a/0x2e0 kernel/printk/printk.c:1084 [] msg_print_text+0x240/0x2d0 kernel/printk/printk.c:1126 [] syslog_print kernel/printk/printk.c:1176 [inline] [] do_syslog kernel/printk/printk.c:1336 [inline] [] do_syslog+0x7f8/0xaf0 kernel/printk/printk.c:1306 [] kmsg_read+0x74/0xa0 fs/proc/kmsg.c:39 [] proc_reg_read+0xfd/0x180 fs/proc/inode.c:202 [] __vfs_read+0x116/0x3c0 fs/read_write.c:434 [] vfs_read+0x134/0x360 fs/read_write.c:456 [] SYSC_read fs/read_write.c:571 [inline] [] SyS_read+0xdc/0x1c0 fs/read_write.c:564 [] entry_SYSCALL_64_fastpath+0x1e/0x9a Code: fe ff ff 66 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 80 67 01 00 65 8b 15 08 d1 d0 7e 81 e2 00 01 1f 00 75 2b 8b 90 50 12 00 00 <83> fa 02 75 20 48 8b 88 58 12 00 00 8b 80 54 12 00 00 48 8b 11