INFO: task syz-executor.2:8098 blocked for more than 140 seconds. Not tainted 4.19.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D24096 8098 1 0x00000004 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3559 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1300 kernel/locking/mutex.c:1072 fuse_lock_inode+0xaf/0xe0 fs/fuse/inode.c:365 fuse_lookup+0x7e/0x3b0 fs/fuse/dir.c:367 __lookup_slow+0x250/0x4b0 fs/namei.c:1672 lookup_slow+0x51/0x70 fs/namei.c:1689 walk_component+0x70a/0x1ee0 fs/namei.c:1811 link_path_walk.part.0+0x8fd/0x1210 fs/namei.c:2142 link_path_walk fs/namei.c:2073 [inline] path_mountpoint+0xe0/0x1e40 fs/namei.c:2695 filename_mountpoint+0x18e/0x390 fs/namei.c:2718 ksys_umount+0x14c/0xd90 fs/namespace.c:1645 __do_sys_umount fs/namespace.c:1671 [inline] __se_sys_umount fs/namespace.c:1669 [inline] __x64_sys_umount+0x50/0x70 fs/namespace.c:1669 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45f277 Code: 0f 86 88 00 00 00 48 83 ec 30 48 89 6c 24 28 48 8d 6c 24 28 31 c0 eb 09 48 8b 4c 24 20 48 8d 41 01 48 83 f8 04 7d 58 48 89 c1 <48> c1 e0 04 48 8b 54 24 40 48 8b 5c 10 08 48 8b 34 10 48 8b 7c 24 RSP: 002b:00007ffdb2a56ec8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045f277 RDX: 0000000000402f28 RSI: 0000000000000002 RDI: 00007ffdb2a56f70 RBP: 00000000000009af R08: 0000000000000000 R09: 0000000000000010 R10: 000000000000000a R11: 0000000000000246 R12: 00007ffdb2a58000 R13: 0000000000ea3940 R14: 0000000000000000 R15: 00007ffdb2a58000 Showing all locks held in the system: 1 lock held by khungtaskd/1080: #0: 0000000087311258 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4436 2 locks held by rsyslogd/7927: #0: 00000000a32275c8 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767 #1: 00000000ae622e81 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1817 [inline] #1: 00000000ae622e81 (&rq->lock){-.-.}, at: __schedule+0x1f8/0x1d80 kernel/sched/core.c:3453 2 locks held by getty/8052: #0: 00000000dcac69b6 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 0000000009b99573 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by getty/8053: #0: 000000008e244c80 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000fde58fdb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by getty/8054: #0: 00000000e3229d82 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 0000000079739674 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by getty/8055: #0: 0000000019c81d23 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000001577559f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by getty/8056: #0: 000000008e2c004a (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 0000000098705446 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by getty/8057: #0: 00000000c5df3e1a (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000009ff06a9e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by getty/8058: #0: 00000000176b2692 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000e013d199 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 2 locks held by syz-executor.2/8098: #0: 00000000dec9d698 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:757 [inline] #0: 00000000dec9d698 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x43/0x70 fs/namei.c:1688 #1: 000000008c150f66 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xaf/0xe0 fs/fuse/inode.c:365 2 locks held by syz-executor.2/3981: #0: 00000000dec9d698 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:757 [inline] #0: 00000000dec9d698 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x43/0x70 fs/namei.c:1688 #1: 000000008c150f66 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xaf/0xe0 fs/fuse/inode.c:365 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1080 Comm: khungtaskd Not tainted 4.19.110-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x962/0xe40 kernel/hung_task.c:287 kthread+0x34a/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 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