[ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.176' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 847.385487][ T8515] NILFS (loop0): broken superblock, retrying with spare superblock (blocksize = 1024) [ 847.397614][ T8515] NILFS (loop0): broken superblock, retrying with spare superblock (blocksize = 2048) [ 847.408844][ T8515] NILFS (loop0): mounting unchecked fs [ 847.425370][ T8515] NILFS (loop0): recovery complete [ 847.448715][ T8520] NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds [ 1005.606374][ T1655] INFO: task syz-executor017:8513 blocked for more than 143 seconds. [ 1005.615578][ T1655] Not tainted 5.10.0-rc3-next-20201116-syzkaller #0 [ 1005.623821][ T1655] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1005.632622][ T1655] task:syz-executor017 state:D stack:27448 pid: 8513 ppid: 8507 flags:0x00004000 [ 1005.642337][ T1655] Call Trace: [ 1005.645687][ T1655] __schedule+0x890/0x2030 [ 1005.650205][ T1655] ? io_schedule_timeout+0x140/0x140 [ 1005.655566][ T1655] ? prepare_to_wait_event+0x129/0x6a0 [ 1005.661127][ T1655] schedule+0xcf/0x270 [ 1005.665368][ T1655] wb_wait_for_completion+0x17b/0x230 [ 1005.671007][ T1655] ? sync_inode_metadata+0xd0/0xd0 [ 1005.676578][ T1655] ? add_wait_queue+0x150/0x150 [ 1005.681624][ T1655] ? rwsem_down_read_slowpath+0xc90/0xc90 [ 1005.688294][ T1655] sync_inodes_sb+0x1a6/0x9d0 [ 1005.693041][ T1655] ? I_BDEV+0x9/0x20 [ 1005.697151][ T1655] ? __filemap_fdatawrite_range+0x1dc/0x380 [ 1005.703111][ T1655] ? try_to_writeback_inodes_sb+0xc0/0xc0 [ 1005.708980][ T1655] ? get_nr_dirty_inodes+0x1b2/0x250 [ 1005.714282][ T1655] sync_filesystem+0x15c/0x260 [ 1005.719226][ T1655] generic_shutdown_super+0x70/0x370 [ 1005.724519][ T1655] kill_block_super+0x97/0xf0 [ 1005.729276][ T1655] deactivate_locked_super+0x94/0x160 [ 1005.734656][ T1655] deactivate_super+0xad/0xd0 [ 1005.739423][ T1655] cleanup_mnt+0x3a3/0x530 [ 1005.743933][ T1655] task_work_run+0xdd/0x190 [ 1005.748572][ T1655] exit_to_user_mode_prepare+0x1f0/0x200 [ 1005.754254][ T1655] syscall_exit_to_user_mode+0x38/0x260 [ 1005.759875][ T1655] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1005.765792][ T1655] RIP: 0033:0x44e0e7 [ 1005.769767][ T1655] Code: Unable to access opcode bytes at RIP 0x44e0bd. [ 1005.776688][ T1655] RSP: 002b:00007fff42061288 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 [ 1005.785098][ T1655] RAX: 0000000000000000 RBX: 00000000000cee4c RCX: 000000000044e0e7 [ 1005.793121][ T1655] RDX: 0000000000400be0 RSI: 0000000000000002 RDI: 00007fff42061330 [ 1005.801160][ T1655] RBP: 0000000000002142 R08: 0000000000000000 R09: 0000000000000009 [ 1005.809545][ T1655] R10: 0000000000000005 R11: 0000000000000206 R12: 00007fff420623e0 [ 1005.817720][ T1655] R13: 0000000001f67880 R14: 0000000000000000 R15: 0000000000000000 [ 1005.826155][ T1655] [ 1005.826155][ T1655] Showing all locks held in the system: [ 1005.833886][ T1655] 2 locks held by kworker/u4:5/225: [ 1005.839163][ T1655] #0: ffff8881413a4138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 [ 1005.849887][ T1655] #1: ffffc9000191fda8 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 [ 1005.861802][ T1655] 1 lock held by khungtaskd/1655: [ 1005.866895][ T1655] #0: ffffffff8b339ce0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 [ 1005.877037][ T1655] 1 lock held by in:imklog/8188: [ 1005.881975][ T1655] #0: ffff888017c8f4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 [ 1005.891235][ T1655] 2 locks held by syz-executor017/8513: [ 1005.896885][ T1655] #0: ffff88801a8500e0 (&type->s_umount_key#49){+.+.}-{3:3}, at: deactivate_super+0xa5/0xd0 [ 1005.907139][ T1655] #1: ffff888143f5e708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x18c/0x9d0 [ 1005.917368][ T1655] [ 1005.919694][ T1655] ============================================= [ 1005.919694][ T1655] [ 1005.928152][ T1655] NMI backtrace for cpu 0 [ 1005.932489][ T1655] CPU: 0 PID: 1655 Comm: khungtaskd Not tainted 5.10.0-rc3-next-20201116-syzkaller #0 [ 1005.942008][ T1655] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 1005.952046][ T1655] Call Trace: [ 1005.955362][ T1655] dump_stack+0x107/0x163 [ 1005.959697][ T1655] nmi_cpu_backtrace.cold+0x44/0xd7 [ 1005.964949][ T1655] ? lapic_can_unplug_cpu+0x80/0x80 [ 1005.970170][ T1655] nmi_trigger_cpumask_backtrace+0x1b3/0x230 [ 1005.976173][ T1655] watchdog+0xd89/0xf30 [ 1005.980320][ T1655] ? trace_sched_process_hang+0x280/0x280 [ 1005.986025][ T1655] kthread+0x3af/0x4a0 [ 1005.990108][ T1655] ? kthread_create_worker_on_cpu+0xf0/0xf0 [ 1005.996017][ T1655] ret_from_fork+0x1f/0x30 [ 1006.000561][ T1655] Sending NMI from CPU 0 to CPUs 1: [ 1006.005857][ C1] NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c9/0x250 [ 1006.007767][ T1655] Kernel panic - not syncing: hung_task: blocked tasks [ 1006.021442][ T1655] CPU: 0 PID: 1655 Comm: khungtaskd Not tainted 5.10.0-rc3-next-20201116-syzkaller #0 [ 1006.030977][ T1655] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 1006.048752][ T1655] Call Trace: [ 1006.052028][ T1655] dump_stack+0x107/0x163 [ 1006.056361][ T1655] panic+0x306/0x73d [ 1006.060238][ T1655] ? __warn_printk+0xf3/0xf3 [ 1006.064808][ T1655] ? lapic_can_unplug_cpu+0x80/0x80 [ 1006.070033][ T1655] ? preempt_schedule_thunk+0x16/0x18 [ 1006.075387][ T1655] ? watchdog.cold+0x22d/0x248 [ 1006.080148][ T1655] ? watchdog+0xc59/0xf30 [ 1006.084486][ T1655] watchdog.cold+0x23e/0x248 [ 1006.089065][ T1655] ? trace_sched_process_hang+0x280/0x280 [ 1006.094780][ T1655] kthread+0x3af/0x4a0 [ 1006.098838][ T1655] ? kthread_create_worker_on_cpu+0xf0/0xf0 [ 1006.104715][ T1655] ret_from_fork+0x1f/0x30 [ 1006.109784][ T1655] Kernel Offset: disabled [ 1006.114110][ T1655] Rebooting in 86400 seconds..