INFO: task syz-executor.0:7985 blocked for more than 143 seconds. Not tainted 5.1.0-rc3+ #53 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D24176 7985 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: 0033:0x45ad07 Code: 94 24 10 00 10 00 48 8b bc 24 20 00 10 00 8b 8c 24 28 00 10 00 8b 9c 24 2c 00 10 00 48 89 e6 48 01 df 48 01 de 48 29 d9 e8 46 ff ff 48 8b ac 24 00 00 10 00 48 81 c4 08 00 10 00 c3 e8 31 f2 RSP: 002b:00007ffc12b69fb8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00000000000a5b3e RCX: 000000000045ad07 RDX: 0000000000402f50 RSI: 0000000000000002 RDI: 00007ffc12b6a060 RBP: 0000000000001098 R08: 000000000000c802 R09: 000000000000000d R10: 0000000000000006 R11: 0000000000000202 R12: 00007ffc12b6b0f0 R13: 0000000001ca1940 R14: 0000000000000000 R15: 00007ffc12b6b0f0 Showing all locks held in the system: 1 lock held by khungtaskd/1041: #0: 000000009409ee87 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5061 1 lock held by rsyslogd/7801: 2 locks held by getty/7945: #0: 0000000084f0abba (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000050f3ecba (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7946: #0: 00000000c75d3721 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000067a7a64b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7947: #0: 00000000e8b76465 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000202afda1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7948: #0: 000000001ce49339 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000006c528ae2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7949: #0: 000000006bf53678 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000003be843f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7950: #0: 000000005f3c9d28 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000fcf77e7e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7951: #0: 000000006b8ee4f7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000007fe66e63 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/7985: #0: 00000000125b8f23 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:779 [inline] #0: 00000000125b8f23 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1685 #1: 00000000974e4a19 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 2 locks held by syz-executor.0/10167: #0: 00000000125b8f23 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:779 [inline] #0: 00000000125b8f23 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1685 #1: 00000000974e4a19 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:367 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1041 Comm: khungtaskd Not tainted 5.1.0-rc3+ #53 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 1 to CPUs 0: