INFO: task syz-executor107:9476 blocked for more than 143 seconds. Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor107 D24176 9476 9475 0x80004002 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 io_schedule+0x1c/0x70 kernel/sched/core.c:5799 wait_on_page_bit_common mm/filemap.c:1175 [inline] wait_on_page_bit+0x27c/0xa60 mm/filemap.c:1224 wait_on_page_writeback+0x1b2/0x4f0 mm/page-writeback.c:2822 __filemap_fdatawait_range+0x145/0x340 mm/filemap.c:526 filemap_fdatawait_keep_errors+0x22/0x30 mm/filemap.c:621 wait_sb_inodes fs/fs-writeback.c:2436 [inline] sync_inodes_sb+0x6e4/0xb50 fs/fs-writeback.c:2558 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x168/0x260 fs/sync.c:48 generic_shutdown_super+0x75/0x370 fs/super.c:448 kill_block_super+0xa0/0x100 fs/super.c:1444 deactivate_locked_super+0x95/0x100 fs/super.c:335 deactivate_super fs/super.c:366 [inline] deactivate_super+0x1bd/0x1e0 fs/super.c:362 cleanup_mnt+0x351/0x4c0 fs/namespace.c:1102 __cleanup_mnt+0x16/0x20 fs/namespace.c:1109 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x909/0x2f20 kernel/exit.c:797 do_group_exit+0x135/0x360 kernel/exit.c:895 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160 prepare_exit_to_usermode+0x321/0x3a0 arch/x86/entry/common.c:195 ret_from_intr+0x26/0x36 RIP: 0033:0x411810 Code: Bad RIP value. RSP: 002b:00007ffc7a9ef2f0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000000000000b RCX: 0000000000402ed0 RDX: 0000000000000001 RSI: 00000000006d50e0 RDI: 000000000000000b RBP: 00000000006d50e0 R08: 0000000000000003 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000001 R13: 0f1414ac00000002 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1116: #0: ffffffff899af980 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/9363: #0: ffff88809acb5120 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:803 2 locks held by getty/9453: #0: ffff888094a4d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9454: #0: ffff888094932090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9455: #0: ffff88809f1ee090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000173b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9456: #0: ffff8880985c3090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000179b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9457: #0: ffff8880a22e1090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017bb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9458: #0: ffff888095bff090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9459: #0: ffff8880a32e1090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900011442e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor107/9476: #0: ffff88809799c0d8 (&type->s_umount_key#45){+.+.}, at: deactivate_super fs/super.c:365 [inline] #0: ffff88809799c0d8 (&type->s_umount_key#45){+.+.}, at: deactivate_super+0x1b5/0x1e0 fs/super.c:362 #1: ffff88809799c8b8 (&s->s_sync_lock){+.+.}, at: wait_sb_inodes fs/fs-writeback.c:2375 [inline] #1: ffff88809799c8b8 (&s->s_sync_lock){+.+.}, at: sync_inodes_sb+0x246/0xb50 fs/fs-writeback.c:2558 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1116 Comm: khungtaskd Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xdf1/0x14e0 kernel/hung_task.c:333 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60