INFO: task kworker/1:4:5227 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:4 state:D stack:21736 pid:5227 tgid:5227 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events request_firmware_work_func Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xeb1/0x41f0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7004 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776 device_lock include/linux/device.h:895 [inline] ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1161 [inline] ath9k_hif_usb_firmware_cb+0x3b2/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1294 request_firmware_work_func+0x13c/0x250 drivers/base/firmware_loader/main.c:1152 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 4 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/30: #0: ffffffff896e05a0 ( rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 3 locks held by kworker/0:2/747: 1 lock held by udevd/2853: 2 locks held by getty/2915: #0: ffff888115d110a0 ( &tty->ldisc_sem ){++++}-{0:0} , at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211 6 locks held by kworker/0:4/5226: #0: ffff888102ab6548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250 #1: ffffc9000315fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251 #2: ffff88810b722198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff88810b722198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88811e435198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff88811e435198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff88811ca48160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #4: ffff88811ca48160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1106 [inline] #4: ffff88811ca48160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xaa/0x600 drivers/base/dd.c:1304 #5: ffffffff8a509628 (input_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8a509628 (input_mutex){+.+.}-{4:4}, at: __input_unregister_device+0x184/0x4d0 drivers/input/input.c:2187 3 locks held by kworker/1:4/5227: #0: ffff88810006b548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250 #1: ffffc9000316fd18 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251 #2: ffff88810b7fa198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff88810b7fa198 (&dev->mutex){....}-{4:4}, at: ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1161 [inline] #2: ffff88810b7fa198 (&dev->mutex){....}-{4:4}, at: ath9k_hif_usb_firmware_cb+0x3b2/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1294 5 locks held by kworker/1:5/5323: 5 locks held by kworker/1:2/9965: 3 locks held by kworker/0:6/11530: #0: ffff888102ab6548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250 #1: ffffc90014b77d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251 #2: ffff88810b7fa198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff88810b7fa198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 1 lock held by syz.1.2071/12739: no locks held by syz.0.2072/12741. 1 lock held by syz.2.2073/12743: 2 locks held by syz-executor/12745: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12757: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12760: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12763: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12785: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12795: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12807: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12808: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4} , at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] , at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12811: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12828: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 1 lock held by syz-executor/12845: 2 locks held by syz-executor/12846: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 1 lock held by syz-executor/12855: 3 locks held by syz-executor/12856: 2 locks held by syz-executor/12857: 2 locks held by syz-executor/12858: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12860: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12863: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 2 locks held by syz-executor/12886: #0: ffffffff8aae0830 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x41e/0x780 net/core/net_namespace.c:577 #1: ffffffff8aaf8e68 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x23/0xb0 net/core/dev.c:2102 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xd25/0x1050 kernel/hung_task.c:515 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events legacy_dvb_usb_read_remote_control RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:407 Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 31 24 f6 fe eb a0 e8 ba 24 f6 RSP: 0018:ffffc9000009f690 EFLAGS: 00000002 RAX: 0000000000000031 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff831f6585 RDI: ffffffff941ae5c0 RBP: ffffffff941ae580 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000031 R14: 0000000000000010 R15: ffffffff831f6520 FS: 0000000000000000(0000) GS:ffff8882686d3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b1a0cb6190 CR3: 000000011718e000 CR4: 00000000003506f0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3264 [inline] serial8250_console_write+0xde8/0x1900 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3183 [inline] console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269 console_flush_all kernel/printk/printk.c:3343 [inline] __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0x103/0x260 kernel/printk/printk.c:3413 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479 _printk+0xcf/0x110 kernel/printk/printk.c:2504 m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline] m920x_rc_query.cold+0x2b/0x30 drivers/media/usb/dvb-usb/m920x.c:188 legacy_dvb_usb_read_remote_control+0x10c/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245