INFO: task syz-executor468:9081 blocked for more than 143 seconds. Not tainted 5.5.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor468 D27312 9081 9079 0x00004000 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+0x1b2/0x1d0 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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x448807 Code: Bad RIP value. RSP: 002b:00007ffd60827898 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000004aa82 RCX: 0000000000448807 RDX: 0000000000400c50 RSI: 0000000000000002 RDI: 00007ffd60827940 RBP: 0000000000002899 R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000206 R12: 00007ffd608289a0 R13: 000000000097e940 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1109: #0: ffffffff899a5680 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/8962: #0: ffff88809a717b60 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9052: #0: ffff8880a0387090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9053: #0: ffff8880a1099090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9054: #0: ffff88809ec0d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000175b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9055: #0: ffff8880a9a75090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000174b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9056: #0: ffff88809fec0090 (&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/9057: #0: ffff88809f8e2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9058: #0: ffff888214881090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900011102e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor468/9081: #0: ffff8880985de0d8 (&type->s_umount_key#41){+.+.}, at: deactivate_super fs/super.c:365 [inline] #0: ffff8880985de0d8 (&type->s_umount_key#41){+.+.}, at: deactivate_super+0x1aa/0x1d0 fs/super.c:362 #1: ffff8880985de8b8 (&s->s_sync_lock){+.+.}, at: wait_sb_inodes fs/fs-writeback.c:2375 [inline] #1: ffff8880985de8b8 (&s->s_sync_lock){+.+.}, at: sync_inodes_sb+0x246/0xb50 fs/fs-writeback.c:2558 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1109 Comm: khungtaskd Not tainted 5.5.0-rc3-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:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60