INFO: task syz-executor.3:13896 blocked for more than 143 seconds. Not tainted 5.0.0-next-20190306 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24376 13896 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 fuse_lookup+0x8e/0x350 fs/fuse/dir.c:335 __lookup_slow+0x27e/0x500 fs/namei.c:1669 lookup_slow+0x58/0x80 fs/namei.c:1686 walk_component+0x74b/0x2000 fs/namei.c:1808 link_path_walk.part.0+0x980/0x1340 fs/namei.c:2139 link_path_walk fs/namei.c:2070 [inline] path_mountpoint+0xe0/0x1e60 fs/namei.c:2692 filename_mountpoint+0x190/0x3c0 fs/namei.c:2715 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2745 ksys_umount+0x167/0xf00 fs/namespace.c:1687 __do_sys_umount fs/namespace.c:1713 [inline] __se_sys_umount fs/namespace.c:1711 [inline] __x64_sys_umount+0x54/0x80 fs/namespace.c:1711 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45aac7 Code: 24 00 00 02 00 48 81 c4 08 00 02 00 c3 e8 a1 f4 ff ff e9 4c ff ff ff 48 8d bc 24 10 00 02 00 48 39 3b 75 8c 48 89 23 eb 87 cc cc cc cc cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 8b 71 10 RSP: 002b:00007ffc6c083f38 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 0000000000057fe5 RCX: 000000000045aac7 RDX: 0000000000402e80 RSI: 0000000000000002 RDI: 00007ffc6c083fe0 RBP: 000000000000004c R08: 0000000000000000 R09: 000000000000000f R10: 000000000000000a R11: 0000000000000206 R12: 00007ffc6c085070 R13: 00000000020ee940 R14: 0000000000000000 R15: 00007ffc6c085070 Showing all locks held in the system: 1 lock held by khungtaskd/1043: #0: 000000000ecd2c96 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5052 1 lock held by rsyslogd/7491: #0: 000000004205bdd1 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7581: #0: 000000002721686c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000008c5595c5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7582: #0: 00000000291796a9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000105f3523 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7583: #0: 000000009c061379 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000c8be159 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7584: #0: 00000000d085ab3a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000797cb712 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7585: #0: 0000000085016b7c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000466d600c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7586: #0: 0000000078a6ab65 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000070fdfecd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7587: #0: 00000000da0832c5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000ed1ec5f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/13896: #0: 00000000354c6a49 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:779 [inline] #0: 00000000354c6a49 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1685 #1: 00000000e8eca9df (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 2 locks held by syz-executor.3/14322: #0: 00000000354c6a49 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:779 [inline] #0: 00000000354c6a49 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1685 #1: 00000000e8eca9df (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1043 Comm: khungtaskd Not tainted 5.0.0-next-20190306 #4 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+0x1be/0x236 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:204 [inline] watchdog+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: