INFO: task syz-executor.2:7564 blocked for more than 140 seconds. Not tainted 4.19.80 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D23592 7564 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3515 schedule+0x92/0x1c0 kernel/sched/core.c:3559 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3617 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1300 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:365 fuse_lookup+0x8e/0x3e0 fs/fuse/dir.c:360 __lookup_slow+0x279/0x500 fs/namei.c:1671 lookup_slow+0x58/0x80 fs/namei.c:1688 walk_component+0x747/0x2000 fs/namei.c:1810 link_path_walk.part.0+0x980/0x1330 fs/namei.c:2141 link_path_walk fs/namei.c:2072 [inline] path_mountpoint+0xe0/0x1e60 fs/namei.c:2694 filename_mountpoint+0x18e/0x390 fs/namei.c:2717 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2747 ksys_umount+0x164/0xe70 fs/namespace.c:1645 __do_sys_umount fs/namespace.c:1671 [inline] __se_sys_umount fs/namespace.c:1669 [inline] __x64_sys_umount+0x54/0x80 fs/namespace.c:1669 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c487 Code: 76 68 48 83 ec 28 48 89 6c 24 20 48 8d 6c 24 20 48 8b 44 24 30 48 89 04 24 48 8b 4c 24 38 48 89 4c 24 08 48 c7 44 24 10 04 00 <00> 00 e8 82 a4 fa ff 48 8b 44 24 18 48 8b 4c 24 30 48 83 c1 08 48 RSP: 002b:00007ffe3fb38558 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 000000000003ddf2 RCX: 000000000045c487 RDX: 0000000000403550 RSI: 0000000000000002 RDI: 00007ffe3fb38600 RBP: 0000000000000315 R08: 0000000000000000 R09: 0000000000000010 R10: 000000000000000a R11: 0000000000000206 R12: 00007ffe3fb39690 R13: 0000000001563940 R14: 0000000000000000 R15: 00007ffe3fb39690 Showing all locks held in the system: 1 lock held by khungtaskd/1037: #0: 00000000e0d8d03c (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4438 2 locks held by rsyslogd/7393: #0: 00000000f09517d0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 #1: 000000004eda9ece (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1821 [inline] #1: 000000004eda9ece (&rq->lock){-.-.}, at: __schedule+0x1f8/0x1dc0 kernel/sched/core.c:3453 2 locks held by getty/7517: #0: 00000000e09c646b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000246aa0bc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7518: #0: 000000005078b14d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000e49c5a3d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7519: #0: 000000009b6b36ce (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000038187d18 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7520: #0: 00000000a41c2ef6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000ae9c2f19 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7521: #0: 0000000043475e4f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000075e53654 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7522: #0: 000000007e252599 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000a7a4575a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7523: #0: 0000000046d53524 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000077f0acde (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by syz-executor.2/7564: #0: 000000006fefa8c0 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:757 [inline] #0: 000000006fefa8c0 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1687 #1: 000000009cb9133e (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:365 2 locks held by syz-executor.2/12884: #0: 000000006fefa8c0 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:757 [inline] #0: 000000006fefa8c0 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1687 #1: 000000009cb9133e (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:365 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1037 Comm: khungtaskd Not tainted 4.19.80 #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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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:203 [inline] watchdog+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 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