INFO: task syz-executor.1:7900 blocked for more than 143 seconds. Not tainted 5.1.0-rc1 #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D24344 7900 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:00007ffccfbbee28 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 000000000007df1f RCX: 000000000045aac7 RDX: 0000000000402e80 RSI: 0000000000000002 RDI: 00007ffccfbbeed0 RBP: 0000000000000711 R08: 0000000000000000 R09: 0000000000000010 R10: 000000000000000a R11: 0000000000000206 R12: 00007ffccfbbff60 R13: 00000000017d5940 R14: 0000000000000000 R15: 00007ffccfbbff60 Showing all locks held in the system: 1 lock held by khungtaskd/1042: #0: 00000000b6a77a4d (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5061 1 lock held by rsyslogd/7772: #0: 00000000f10260da (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7862: #0: 000000002609826a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000373fef17 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7863: #0: 0000000026477fb6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000003869206f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7864: #0: 0000000004359613 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000041ec89a9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7865: #0: 00000000e6d73a47 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000c01a5680 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7866: #0: 00000000b79ec1ad (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000e30ff2a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7867: #0: 00000000035cf297 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000007ab0db4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7868: #0: 00000000e14c0b4d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000008e2910 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.1/7900: #0: 000000006c2235aa (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:779 [inline] #0: 000000006c2235aa (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1685 #1: 00000000a6a67184 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 2 locks held by syz-executor.1/20983: #0: 000000006c2235aa (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:779 [inline] #0: 000000006c2235aa (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1685 #1: 00000000a6a67184 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1042 Comm: khungtaskd Not tainted 5.1.0-rc1 #28 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: