rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (9645 ticks this GP) idle=5dcc/1/0x4000000000000000 softirq=96515/96516 fqs=4863 rcu: hardirqs softirqs csw/system rcu: number: 5824 6925 0 rcu: cputime: 0 752 43174 ==> 52550(ms) rcu: (detected by 1, t=10507 jiffies, g=125537, q=13073 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 18 Comm: migration/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Stopper: 0x0 <- 0x0 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 c3 cc cc cc cc e8 91 75 f4 fe eb a0 e8 1a 76 f4 RSP: 0018:ffffc900000074a0 EFLAGS: 00000002 RAX: 0000000000000037 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff83240745 RDI: ffffffff941dcda0 RBP: ffffffff941dcd60 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000037 R14: 0000000000000010 R15: ffffffff832406e0 FS: 0000000000000000(0000) GS:ffff8882686a5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31923ffc CR3: 00000000094ac000 CR4: 00000000003506f0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3217 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3279 [inline] serial8250_console_write+0xde8/0x1900 drivers/tty/serial/8250/8250_port.c:3357 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_ctl_callback.cold+0x41/0x8c drivers/input/misc/yealink.c:456 __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:finish_task_switch.isra.0+0x21a/0xa20 kernel/sched/core.c:5245 Code: 08 3c 03 0f 8e 26 06 00 00 c7 83 00 0d 00 00 00 00 00 00 48 8d 7b 48 e8 14 41 ec 05 e8 6f e1 36 00 fb 49 8d bc 24 e8 15 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 RSP: 0018:ffffc9000012fca0 EFLAGS: 00000202 RAX: 0000000000000dbf RBX: ffff8881f5639680 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff890c81fc RDI: ffff88810229d168 RBP: ffffc9000012fce0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88810229bb80 R13: ffff888119e60000 R14: 0000000000000000 R15: ffff8881f563a380 context_switch kernel/sched/core.c:5391 [inline] __schedule+0x1140/0x47e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 smpboot_thread_fn+0x893/0xaa0 kernel/smpboot.c:156 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 rcu: rcu_preempt kthread timer wakeup didn't happen for 1890 jiffies! g125537 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 yealink 8-1:36.0: urb_irq_callback - urb status -71 rcu: Possible timer handling issue on cpu=1 timer-softirq=26503 yealink 8-1:36.0: unexpected response 0 rcu: rcu_preempt kthread starved for 1892 jiffies! g125537 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->cpu=1 yealink 8-1:36.0: urb_ctl_callback - urb status -71 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. yealink 8-1:36.0: urb_irq_callback - urb status -71 rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R yealink 8-1:36.0: unexpected response 0 stack:28056 pid:15 tgid:15 ppid:2 task_flags:0x208040 flags:0x00080000 yealink 8-1:36.0: urb_ctl_callback - urb status -71 Call Trace: yealink 8-1:36.0: urb_irq_callback - urb status -71 context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1138/0x47e0 kernel/sched/core.c:7189 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 yealink 8-1:36.0: urb_ctl_callback - urb status -71 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 kthread+0x370/0x450 kernel/kthread.c:436 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 rcu: Stack dump where RCU GP kthread last ran: yealink 8-1:36.0: urb_ctl_callback - urb status -71 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) yealink 8-1:36.0: urb_irq_callback - urb status -71 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 yealink 8-1:36.0: unexpected response 0 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 yealink 8-1:36.0: urb_ctl_callback - urb status -71 Code: 44 b7 01 c3 cc cc cc cc 0f 1f 00 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 63 ad 18 00 fb f4 bc f2 02 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 yealink 8-1:36.0: urb_irq_callback - urb status -71 RSP: 0018:ffffc9000013fe00 EFLAGS: 00000246 yealink 8-1:36.0: unexpected response 0 RAX: 0000000000c7211d RBX: ffff888102299dc0 RCX: ffffffff876dd475 yealink 8-1:36.0: urb_ctl_callback - urb status -71 RDX: 0000000000000000 RSI: ffffffff890c81fc RDI: ffffffff87b08de0 yealink 8-1:36.0: urb_irq_callback - urb status -71 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed103eae673d yealink 8-1:36.0: unexpected response 0 R10: ffff8881f57339eb R11: 0000000000000000 R12: 0000000000000001 yealink 8-1:36.0: urb_ctl_callback - urb status -71 R13: ffffed10204533b8 R14: 0000000000000001 R15: ffffffff8af095d0 yealink 8-1:36.0: urb_irq_callback - urb status -71 FS: 0000000000000000(0000) GS:ffff8882687a5000(0000) knlGS:0000000000000000 yealink 8-1:36.0: unexpected response 0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 yealink 8-1:36.0: urb_ctl_callback - urb status -71 CR2: 00007f647c54bd44 CR3: 0000000122a98000 CR4: 00000000003506f0 yealink 8-1:36.0: urb_irq_callback - urb status -71 Call Trace: yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 yealink 8-1:36.0: urb_irq_callback - urb status -71 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 yealink 8-1:36.0: unexpected response 0 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x464/0x590 kernel/sched/idle.c:352 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451 yealink 8-1:36.0: unexpected response 0 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 common_startup_64+0x13e/0x148 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_ctl_callback - urb status -71 yealink 8-1:36.0: urb_irq_callback - urb status -71 yealink 8-1:36.0: unexpected response 0 yealink 8-1:36.0: urb_irq_callback - usb_submit_urb failed -19