INFO: task syz.8.5401:26021 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.5401 state:D stack:24688 pid:26021 ppid: 25570 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093 __down_common+0x289/0x3b0 kernel/locking/semaphore.c:228 down+0x7e/0xd0 kernel/locking/semaphore.c:63 console_lock+0x29/0x70 kernel/printk/printk.c:2557 con_install+0x94/0x720 drivers/tty/vt/vt.c:3381 tty_driver_install_tty drivers/tty/tty_io.c:1317 [inline] tty_init_dev+0xbb/0x470 drivers/tty/tty_io.c:1431 tty_open_by_driver drivers/tty/tty_io.c:2100 [inline] tty_open+0x7e8/0xcd0 drivers/tty/tty_io.c:2148 chrdev_open+0x585/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7f7/0xf90 fs/open.c:826 do_open fs/namei.c:3659 [inline] path_openat+0x2718/0x2fb0 fs/namei.c:3793 do_filp_open+0x1df/0x400 fs/namei.c:3820 do_sys_openat2+0x14b/0x500 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f5a2d927d8e RSP: 002b:00007f5a2bbbdb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f5a2bbbe6c0 RCX: 00007f5a2d927d8e RDX: 0000000000000002 RSI: 00007f5a2bbbdc00 RDI: ffffffffffffff9c RBP: 00007f5a2d9feb20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5a2dbee038 R14: 00007f5a2dbedfa0 R15: 00007ffc575b5738 Showing all locks held in the system: 3 locks held by kworker/0:1/13: 1 lock held by khungtaskd/27: #0: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 3 locks held by dhcpcd/3853: 3 locks held by kworker/u5:4/4200: #0: ffff88805eabc938 ((wq_completion)hci11){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000301fd00 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffff88803adc93f0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open+0xa4/0x12a0 net/bluetooth/hci_core.c:1464 2 locks held by kworker/u4:10/4348: 4 locks held by kworker/u4:16/6410: 2 locks held by kworker/0:13/14284: #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000340fd00 (console_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 4 locks held by kworker/0:15/14286: #0: ffff88814179ad38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000380fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffff888024bc2220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #2: ffff888024bc2220 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5260 drivers/usb/core/hub.c:5832 #3: ffff888080726220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #3: ffff888080726220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:974 2 locks held by getty/16228: #0: ffff88814d845098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900013af2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158 3 locks held by kworker/u5:1/24291: #0: ffff88802549e138 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc90002fefd00 ((work_completion)(&hdev->connectable_update)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffff88807e0dd3f0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_req_sync net/bluetooth/hci_request.c:278 [inline] #2: ffff88807e0dd3f0 (&hdev->req_lock){+.+.}-{3:3}, at: connectable_update_work+0x35/0xe0 net/bluetooth/hci_request.c:2726 5 locks held by syz.6.5204/25296: 2 locks held by syz.8.5401/26021: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 #1: ffff888060fe01c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x6f/0x470 drivers/tty/tty_io.c:1430 1 lock held by syz.9.5474/26291: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.7.5505/26397: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.5.5576/26711: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.2.5614/26860: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.4.5646/27000: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.3.5649/27041: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.1.5677/27210: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823 3 locks held by syz-executor/27423: 1 lock held by syz.9.5764/27747: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 1 lock held by syz.6.5784/27761: #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148 6 locks held by syz-executor/27838: 4 locks held by udevd/27937: #0: ffff88806595e790 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182 #1: ffff888033b45c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x55/0x3c0 fs/kernfs/file.c:112 #2: ffff8880343d2490 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x75/0x3c0 fs/kernfs/file.c:113 #3: ffff888080726220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline] #3: ffff888080726220 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2408 2 locks held by syz-executor/27962: #0: ffffffff8e25fe10 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x324/0x5b0 net/core/net_namespace.c:499 #1: ffffffff8e26bd48 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_init_net+0x234/0x710 net/ipv4/ip_tunnel.c:1083 1 lock held by dhcpcd/27990: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe1b/0xe60 kernel/hung_task.c:369 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287