INFO: task kworker/0:2:310 blocked for more than 122 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:2 state:D stack:0 pid:310 tgid:310 ppid:2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:6026 [inline] __schedule+0x1399/0x1fa0 kernel/sched/core.c:7880 __schedule_loop kernel/sched/core.c:7961 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7976 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8033 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 usb_audio_probe+0x39d/0x1d60 sound/usb/card.c:887 usb_probe_interface+0x6ac/0xc00 drivers/usb/core/driver.c:400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_set_configuration+0x1acf/0x20b0 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254 usb_probe_device+0x1d1/0x380 drivers/usb/core/driver.c:295 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_new_device+0x9f8/0x15b0 drivers/usb/core/hub.c:2703 hub_port_connect drivers/usb/core/hub.c:5574 [inline] hub_port_connect_change drivers/usb/core/hub.c:5714 [inline] port_event drivers/usb/core/hub.c:5878 [inline] hub_event+0x30c6/0x4700 drivers/usb/core/hub.c:5960 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d1/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 kthread+0x2c6/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 INFO: task kworker/1:4:375 blocked for more than 123 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:4 state:D stack:0 pid:375 tgid:375 ppid:2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:6026 [inline] __schedule+0x1399/0x1fa0 kernel/sched/core.c:7880 __schedule_loop kernel/sched/core.c:7961 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7976 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8033 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 usb_audio_probe+0x39d/0x1d60 sound/usb/card.c:887 usb_probe_interface+0x6ac/0xc00 drivers/usb/core/driver.c:400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_set_configuration+0x1acf/0x20b0 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254 usb_probe_device+0x1d1/0x380 drivers/usb/core/driver.c:295 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_new_device+0x9f8/0x15b0 drivers/usb/core/hub.c:2703 hub_port_connect drivers/usb/core/hub.c:5574 [inline] hub_port_connect_change drivers/usb/core/hub.c:5714 [inline] port_event drivers/usb/core/hub.c:5878 [inline] hub_event+0x30c6/0x4700 drivers/usb/core/hub.c:5960 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d1/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 kthread+0x2c6/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 INFO: task kworker/1:5:453 blocked for more than 124 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:5 state:D stack:0 pid:453 tgid:453 ppid:2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:6026 [inline] __schedule+0x1399/0x1fa0 kernel/sched/core.c:7880 __schedule_loop kernel/sched/core.c:7961 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7976 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8033 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 usb_audio_probe+0x39d/0x1d60 sound/usb/card.c:887 usb_probe_interface+0x6ac/0xc00 drivers/usb/core/driver.c:400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_set_configuration+0x1acf/0x20b0 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254 usb_probe_device+0x1d1/0x380 drivers/usb/core/driver.c:295 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_new_device+0x9f8/0x15b0 drivers/usb/core/hub.c:2703 hub_port_connect drivers/usb/core/hub.c:5574 [inline] hub_port_connect_change drivers/usb/core/hub.c:5714 [inline] port_event drivers/usb/core/hub.c:5878 [inline] hub_event+0x30c6/0x4700 drivers/usb/core/hub.c:5960 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d1/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 kthread+0x2c6/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 7d76481da05fb6652dc975f640030f74837f9139 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120 dump_stack+0x19/0x20 lib/dump_stack.c:129 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline] watchdog+0xdad/0xf00 kernel/hung_task.c:423 kthread+0x2c6/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 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 7d76481da05fb6652dc975f640030f74837f9139 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_out+0x85/0xd0 drivers/tty/serial/8250/8250_port.c:413 Code: fe 44 89 e1 41 d3 e6 49 83 c7 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 64 ec bb fe 45 03 37 89 d8 44 89 f2 ee <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 e1 80 e1 07 RSP: 0018:ffffc900000960a8 EFLAGS: 00000002 RAX: 000000000000002e RBX: 000000000000002e RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 00000000000fffff RDI: 0000000000100000 RBP: ffffc900000960d0 R08: ffff8881076ac107 R09: 1ffff11020ed5820 R10: 0000000000000000 R11: ffffffff83240df0 R12: 0000000000000000 R13: dffffc0000000000 R14: 00000000000003f8 R15: ffffffff88c1f4c8 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2df18ff8 CR3: 000000010cb38000 CR4: 00000000003526b0 Call Trace: serial_out drivers/tty/serial/8250/8250.h:142 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x16d6/0x21a0 drivers/tty/serial/8250/8250_port.c:3421 univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396 console_emit_next_record kernel/printk/printk.c:3151 [inline] console_flush_all+0x5fd/0xac0 kernel/printk/printk.c:3239 __console_flush_and_unlock kernel/printk/printk.c:3298 [inline] console_unlock+0xf8/0x2c0 kernel/printk/printk.c:3338 vprintk_emit+0x282/0x650 kernel/printk/printk.c:2462 dev_vprintk_emit+0x359/0x420 drivers/base/core.c:4962 dev_printk_emit+0xef/0x150 drivers/base/core.c:4973 __dev_printk+0x17f/0x1b0 drivers/base/core.c:4985 _dev_err+0x11f/0x180 drivers/base/core.c:5028 parse_uac2_sample_rate_range+0xa66/0xd30 sound/usb/format.c:398 parse_audio_format_rates_v2v3+0x303/0x1a30 sound/usb/format.c:619 parse_audio_format_ii sound/usb/format.c:777 [inline] snd_usb_parse_audio_format+0x4c1/0x750 sound/usb/format.c:798 snd_usb_get_audioformat_uac12 sound/usb/stream.c:857 [inline] __snd_usb_parse_audio_interface+0x1681/0x47d0 sound/usb/stream.c:1202 snd_usb_parse_audio_interface+0x3e/0xd0 sound/usb/stream.c:1280 create_standard_audio_quirk+0x63/0x130 sound/usb/quirks.c:101 snd_usb_create_quirk sound/usb/quirks.c:541 [inline] create_composite_quirk+0x220/0x540 sound/usb/quirks.c:49 snd_usb_create_quirk+0xab/0x130 sound/usb/quirks.c:541 usb_audio_probe+0xb62/0x1d60 sound/usb/card.c:960 usb_probe_interface+0x6ac/0xc00 drivers/usb/core/driver.c:400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_set_configuration+0x1acf/0x20b0 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254 usb_probe_device+0x1d1/0x380 drivers/usb/core/driver.c:295 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d8/0x890 drivers/base/dd.c:657 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534 device_add+0x80c/0xbf0 drivers/base/core.c:3692 usb_new_device+0x9f8/0x15b0 drivers/usb/core/hub.c:2703 hub_port_connect drivers/usb/core/hub.c:5574 [inline] hub_port_connect_change drivers/usb/core/hub.c:5714 [inline] port_event drivers/usb/core/hub.c:5878 [inline] hub_event+0x30c6/0x4700 drivers/usb/core/hub.c:5960 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d1/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 kthread+0x2c6/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244