INFO: task kworker/0:6:5861 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:6 state:D stack:19384 pid:5861 ppid:2 flags:0x00004000 Workqueue: events console_callback Call Trace: context_switch kernel/sched/core.c:5393 [inline] __schedule+0x15ae/0x4700 kernel/sched/core.c:6722 schedule+0xbd/0x170 kernel/sched/core.c:6796 schedule_timeout+0xc1/0x2d0 kernel/time/timer.c:2144 ___down_common kernel/locking/semaphore.c:229 [inline] __down_common+0x30e/0x650 kernel/locking/semaphore.c:250 down+0x80/0xd0 kernel/locking/semaphore.c:64 console_lock+0x145/0x1b0 kernel/printk/printk.c:2686 console_callback+0x6a/0x440 drivers/tty/vt/vt.c:2936 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8e1322e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6669 3 locks held by kworker/u4:8/3469: #0: ffff88802dcbe138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff88802dcbe138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000ca2fd00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000ca2fd00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4737 2 locks held by dhcpcd/5443: #0: ffff88801aeca690 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0xf4/0x7a0 net/netlink/af_netlink.c:2341 #1: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0x77c/0xec0 net/netlink/af_netlink.c:2268 2 locks held by getty/5538: #0: ffff88802ee140a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032862f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 3 locks held by kworker/0:5/5795: #0: ffff888018c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888018c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000436fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000436fd00 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 2 locks held by kworker/0:6/5861: #0: ffff888018c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888018c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc90004787d00 (console_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc90004787d00 (console_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 6 locks held by syz.6.5008/25873: 2 locks held by syz.5.5159/26543: #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline] #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x211/0xcc0 drivers/tty/tty_io.c:2129 #1: ffff8880797b21c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x74/0x4c0 drivers/tty/tty_io.c:1415 1 lock held by syz.2.5181/26671: #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline] #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x211/0xcc0 drivers/tty/tty_io.c:2129 3 locks held by kworker/0:7/26876: 1 lock held by syz.9.5220/26986: #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd0/0x2c0 drivers/tty/pty.c:823 1 lock held by syz.8.5262/27175: #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd0/0x2c0 drivers/tty/pty.c:823 1 lock held by syz.1.5300/27325: #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline] #0: ffffffff8e8ab988 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x211/0xcc0 drivers/tty/tty_io.c:2129 7 locks held by syz-executor/27500: #0: ffff88807ec92418 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580 #1: ffff888072d94c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343 #2: ffff8880258b57c8 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8880258b57c8 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344 #3: ffffffff8ecac4c8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:209 #4: ffff88802b09a130 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1094 [inline] #4: ffff88802b09a130 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] #4: ffff88802b09a130 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa7/0x6f0 drivers/base/dd.c:1371 #5: ffff88807a9f7250 (&devlink->lock_key#20){+.+.}-{3:3}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1676 #6: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3f/0x180 drivers/net/netdevsim/netdev.c:417 3 locks held by kworker/u4:14/27538: #0: ffff888018c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888018c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000500fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000500fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286 2 locks held by syz.3.5348/27601: #0: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline] #0: ffffffff8f3e8208 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ed/0xf90 net/core/rtnetlink.c:6486 #1: ffffffff8e137cb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline] #1: ffffffff8e137cb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf59/0xfa0 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293