INFO: task kworker/1:4:5242 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:21800 pid:5242 tgid:5242 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events request_firmware_work_func Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1138/0x47e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820 device_lock include/linux/device.h:1040 [inline] ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1161 [inline] ath9k_hif_usb_firmware_cb+0x3b5/0x530 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+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 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: 2 locks held by kworker/0:1/11: 2 locks held by kworker/u8:0/12: 3 locks held by kworker/1:1/28: #0: ffff88810006b140 ( (wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc900001e7d18 (free_ipc_work ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffffffff896ea4a8 ( rcu_state.exp_mutex ){+.+.}-{4:4} , at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by khungtaskd/30: #0: ffffffff896de960 (rcu_read_lock ){....}-{1:3} , at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] , at: rcu_read_lock include/linux/rcupdate.h:838 [inline] , at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:2/37: #0: ffff8881000ac940 ((wq_completion)events_unbound #2 ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90000277d18 ( (work_completion)(&sub_info->work)){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 2 locks held by kworker/u8:4/62: 2 locks held by kworker/u8:8/336: #0: ffff8881000ac940 ( (wq_completion)events_unbound #2 ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90001cc7d18 ( (work_completion)(&sub_info->work) ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 5 locks held by kworker/0:2/347: 4 locks held by kworker/u8:9/2551: #0: ffff888100e98940 ( (wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90005d1fd18 ( net_cleanup_work){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffffffff8aadc468 (pernet_ops_rwsem ){++++}-{4:4} , at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673 #3: ffffffff896ea378 ( rcu_state.barrier_mutex ){+.+.}-{4:4} , at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3828 2 locks held by udevd/2855: 2 locks held by getty/2918: #0: ffff888115d710a0 ( &tty->ldisc_sem){++++}-{0:0} , at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000452e8 ( &ldata->atomic_read_lock){+.+.}-{4:4} , at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211 5 locks held by kworker/0:3/5223: 3 locks held by kworker/1:4/5242: #0: ffff88810006b140 ( (wq_completion)events ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc9000212fd18 ( (work_completion)(&fw_work->work) ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffff88810b7eb1d8 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: ath9k_hif_usb_firmware_fail drivers/net/wireless/ath/ath9k/hif_usb.c:1161 [inline] , at: ath9k_hif_usb_firmware_cb+0x3b5/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1294 5 locks held by kworker/1:6/5348: #0: ffff888105efd140 ( (wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289 #1: ffffc90001fbfd18 ( (work_completion)(&hub->events) ){+.+.}-{0:0} , at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290 #2: ffff88810bbab1d8 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88811e3c61d8 ( &dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff88811e3f61a0 ( &dev->mutex ){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] ){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] ){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1372 4 locks held by kworker/0:6/5742: 4 locks held by kworker/0:7/6550: 1 lock held by syz-executor/6992: #0: ffffffff8aadc468 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575 2 locks held by syz-executor/6994: 2 locks held by syz-executor/7013: #0: ffffffff8aadc468 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575 #1: ffffffff896ea4a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz-executor/7016: #0: ffffffff8aadc468 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575 2 locks held by syz-executor/7044: 9 locks held by syz-executor/7056: 2 locks held by kworker/u8:1/7079: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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:162 [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:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 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: yealink 2-1:36.0: unexpected response 0 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7044 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:408 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 e9 96 fa 4d 04 e8 61 ab f5 fe eb a0 e8 ea ab f5 RSP: 0018:ffffc90000007490 EFLAGS: 00000002 RAX: 0000000000000033 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff8322f515 RDI: ffffffff941da800 RBP: ffffffff941da7c0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000033 R14: 0000000000000010 R15: ffffffff8322f4b0 FS: 0000000000000000(0000) GS:ffff8882686a5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc4878f5fc0 CR3: 000000011526c000 CR4: 00000000003506f0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3220 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3282 [inline] serial8250_console_write+0xde8/0x1900 drivers/tty/serial/8250/8250_port.c:3360 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 dev_vprintk_emit+0x394/0x3e0 drivers/base/core.c:4930 dev_printk_emit+0xd2/0x10d drivers/base/core.c:4941 __dev_printk+0xcb/0x100 drivers/base/core.c:4953 _dev_err+0xef/0x127 drivers/base/core.c:4996 urb_irq_callback.cold+0x81/0xfd drivers/input/misc/yealink.c:435 __usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741 dummy_timer+0xda1/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:2005 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2011 handle_softirqs+0x1dd/0x9e0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x70 kernel/kcov.c:217 Code: 44 0b a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 11 0a be 05 8b 82 0c 16 00 00 85 c0 74 f1 8b 82 e8 15 00 00 <83> f8 02 75 e6 48 8b 8a f0 15 00 00 8b 92 ec 15 00 00 48 8b 01 48 RSP: 0018:ffffc900062b7570 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8202c77d RDX: ffff8881190fbb80 RSI: ffffffff8202c792 RDI: ffff8881190fbb80 RBP: ffffc900062b7738 R08: 0000000000000005 R09: 00000000ff000000 R10: 00000000ffffffff R11: 0000000000000000 R12: ffffea0004aa9e00 R13: 00007f1a17ad5000 R14: 0000000000000000 R15: 800000012aa78007 zap_present_folio_ptes mm/memory.c:1674 [inline] zap_present_ptes mm/memory.c:1730 [inline] do_zap_pte_range mm/memory.c:1832 [inline] zap_pte_range mm/memory.c:1934 [inline] zap_pmd_range mm/memory.c:2020 [inline] zap_pud_range mm/memory.c:2048 [inline] zap_p4d_range mm/memory.c:2069 [inline] __zap_vma_range+0x1ce2/0x4090 mm/memory.c:2109 unmap_vmas+0x299/0x5f0 mm/memory.c:2178 exit_mmap+0x1ef/0xa10 mm/mmap.c:1300 __mmput kernel/fork.c:1178 [inline] mmput+0xe0/0x430 kernel/fork.c:1201 exit_mm kernel/exit.c:582 [inline] do_exit+0x8b2/0x2af0 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119 get_signal+0x20ff/0x2210 kernel/signal.c:3037 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x83/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x682/0x7f0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1a181b7fd7 Code: Unable to access opcode bytes at 0x7f1a181b7fad. RSP: 002b:00007ffefb21cdc0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: 0000000000000028 RBX: 000055557ba48500 RCX: 00007f1a181b7fd7 RDX: 0000000000000028 RSI: 00007f1a18fa4670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffefb21ce24 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f1a18fa4670 R15: 0000000000000000