rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (7967 ticks this GP) idle=3d1c/1/0x4000000000000000 softirq=63365/63365 fqs=35 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/1:b..l rcu: (detected by 1, t=10723 jiffies, g=54933, q=276 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 19 Comm: migration/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Stopper: 0x0 <- 0x0 RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:407 Code: 3e a4 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 cc ee 09 fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 47 ef 32 06 cc 44 89 f9 80 e1 07 38 c1 RSP: 0018:ffffc900000070d0 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000017b7d RDI: 0000000000017b7e RBP: 00000000000003f9 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff851c04d0 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff99d1bfc0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125d0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000027a030 CR3: 0000000077516000 CR4: 00000000003526f0 DR0: 0000000000000006 DR1: 0000000000000000 DR2: 0000000000000080 DR3: 000000000f000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: serial_out drivers/tty/serial/8250/8250.h:142 [inline] serial8250_clear_IER drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x5f2/0x1ba0 drivers/tty/serial/8250/8250_port.c:3307 console_emit_next_record kernel/printk/printk.c:3111 [inline] console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3298 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 dev_vprintk_emit+0x337/0x3f0 drivers/base/core.c:4914 dev_printk_emit+0xe0/0x130 drivers/base/core.c:4925 _dev_err+0x10a/0x160 drivers/base/core.c:4980 urb_ctl_callback+0x1d9/0x290 drivers/input/misc/yealink.c:456 __usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1661 dummy_timer+0x85f/0x44c0 drivers/usb/gadget/udc/dummy_hcd.c:1995 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858 handle_softirqs+0x286/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5193 Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 27 05 00 00 4c 8b 75 d0 4c 89 e7 e8 ef 5b bd 09 e8 aa b8 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 58 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc90000187a18 EFLAGS: 00000286 RAX: 641633bb4cafe400 RBX: 0000000000000000 RCX: 641633bb4cafe400 RDX: 0000000000000000 RSI: ffffffff8d7e8390 RDI: ffffffff8bc076e0 RBP: ffffc90000187a70 R08: ffffffff8f9e1177 R09: 1ffffffff1f3c22e R10: dffffc0000000000 R11: fffffbfff1f3c22f R12: ffff88801c2e3c80 R13: dffffc0000000000 R14: ffff88801c2c9e40 R15: ffff8880b863abd8 context_switch kernel/sched/core.c:5328 [inline] __schedule+0x17a0/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 smpboot_thread_fn+0x5bd/0xa60 kernel/smpboot.c:156 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:kworker/0:0 state:R running task stack:21000 pid:9 tgid:9 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__read_once_word_nocheck+0x3/0x10 include/asm-generic/rwonce.h:67 Code: b1 00 48 ba 00 00 00 00 00 fc ff df e9 88 fc ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 07 58 f8 da 09 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc900000e66b0 EFLAGS: 00000202 RAX: ffffffff85cda705 RBX: ffffc900000e75c8 RCX: 1ffff9200001cc01 RDX: ffffffff90777348 RSI: 0000000000000002 RDI: ffffc900000e75c8 RBP: 1ffff9200001ccf2 R08: 0000000000000001 R09: ffffffff8173cd25 R10: ffffc900000e67d8 R11: ffffffff81ac6cd0 R12: ffffc900000e8000 R13: 1ffff9200001ccf3 R14: ffffc900000e6788 R15: ffffc900000e0000 deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline] unwind_next_frame+0xc3c/0x2390 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4955 [inline] slab_alloc_node mm/slub.c:5265 [inline] kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5272 skb_clone+0x212/0x3a0 net/core/skbuff.c:2050 do_one_broadcast net/netlink/af_netlink.c:1457 [inline] netlink_broadcast_filtered+0x6ae/0x1000 net/netlink/af_netlink.c:1535 netlink_broadcast+0x37/0x50 net/netlink/af_netlink.c:1559 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline] kobject_uevent_net_broadcast+0x378/0x560 lib/kobject_uevent.c:410 kobject_uevent_env+0x55b/0x8c0 lib/kobject_uevent.c:608 really_probe+0x745/0x9e0 drivers/base/dd.c:709 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:959 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:462 __device_attach+0x2b8/0x400 drivers/base/dd.c:1031 bus_probe_device+0x185/0x260 drivers/base/bus.c:537 device_add+0x7b6/0xb50 drivers/base/core.c:3689 usb_set_configuration+0x1a87/0x20e0 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250 usb_probe_device+0x1c4/0x390 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x26d/0x9e0 drivers/base/dd.c:659 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:959 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:462 __device_attach+0x2b8/0x400 drivers/base/dd.c:1031 bus_probe_device+0x185/0x260 drivers/base/bus.c:537 device_add+0x7b6/0xb50 drivers/base/core.c:3689 usb_new_device+0xa39/0x16f0 drivers/usb/core/hub.c:2694 hub_port_connect drivers/usb/core/hub.c:5566 [inline] hub_port_connect_change drivers/usb/core/hub.c:5706 [inline] port_event drivers/usb/core/hub.c:5870 [inline] hub_event+0x2958/0x4a20 drivers/usb/core/hub.c:5952 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10654 jiffies! g54933 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 yealink 2-1:36.0: urb_irq_callback - urb status -71 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. yealink 2-1:36.0: unexpected response 0 rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R yealink 2-1:36.0: urb_ctl_callback - urb status -71 running task stack:26984 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 yealink 2-1:36.0: urb_irq_callback - urb status -71 Call Trace: yealink 2-1:36.0: unexpected response 0 context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 yealink 2-1:36.0: urb_ctl_callback - urb status -71 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 kthread+0x711/0x8a0 kernel/kthread.c:463 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) yealink 2-1:36.0: urb_irq_callback - urb status -71 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 yealink 2-1:36.0: unexpected response 0 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 yealink 2-1:36.0: urb_ctl_callback - urb status -71 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 21 1c 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 yealink 2-1:36.0: urb_irq_callback - urb status -71 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 yealink 2-1:36.0: unexpected response 0 RAX: c94369fbb736d400 RBX: ffffffff8196bc07 RCX: c94369fbb736d400 yealink 2-1:36.0: urb_ctl_callback - urb status -71 RDX: 0000000000000001 RSI: ffffffff8d7e8390 RDI: ffffffff8bc076e0 yealink 2-1:36.0: urb_irq_callback - urb status -71 RBP: ffffc90000197f10 R08: ffff8880b8732fdb R09: 1ffff110170e65fb yealink 2-1:36.0: unexpected response 0 R10: dffffc0000000000 R11: ffffed10170e65fc R12: ffffffff8f9e1170 yealink 2-1:36.0: urb_ctl_callback - urb status -71 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100385cb58 yealink 2-1:36.0: urb_irq_callback - urb status -71 FS: 0000000000000000(0000) GS:ffff888125e0c000(0000) knlGS:0000000000000000 yealink 2-1:36.0: unexpected response 0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 yealink 2-1:36.0: urb_ctl_callback - urb status -71 CR2: 00007ff88bd3bd1c CR3: 000000002881c000 CR4: 00000000003526f0 yealink 2-1:36.0: urb_irq_callback - urb status -71 Call Trace: yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 yealink 2-1:36.0: urb_irq_callback - urb status -71 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 yealink 2-1:36.0: unexpected response 0 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 yealink 2-1:36.0: unexpected response 0 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 yealink 2-1:36.0: urb_ctl_callback - urb status -71 common_startup_64+0x13e/0x147 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_irq_callback - urb status -71 yealink 2-1:36.0: unexpected response 0 yealink 2-1:36.0: urb_ctl_callback - urb status -71 yealink 2-1:36.0: urb_ctl_callback - usb_submit_urb failed -19 vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun