rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P31215/1:b..l rcu: (detected by 1, t=10502 jiffies, g=688425, q=1535 ncpus=2) task:syz.2.16140 state:R running task stack:25488 pid:31215 tgid:31211 ppid:24974 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] wp_page_copy mm/memory.c:3976 [inline] do_wp_page+0x3ec0/0x4c70 mm/memory.c:4336 handle_pte_fault mm/memory.c:6395 [inline] __handle_mm_fault mm/memory.c:6517 [inline] handle_mm_fault+0x1490/0x3080 mm/memory.c:6686 do_user_addr_fault+0x744/0x1340 arch/x86/mm/fault.c:1394 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0010:__put_user_nocheck_4+0x3/0x20 arch/x86/lib/putuser.S:104 Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca e9 57 91 03 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc9000e62f8d8 EFLAGS: 00050202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00002000001b9030 RDX: ffff888029378000 RSI: 0000000000000002 RDI: 00000000ffffffff RBP: ffffc9000e62fa50 R08: ffffc9000e62f6a7 R09: 1ffff92001cc5ed4 R10: dffffc0000000000 R11: fffff52001cc5ed5 R12: 1ffff92001cc5f28 R13: 0000000000000002 R14: 00002000001b9000 R15: dffffc0000000000 ____sys_recvmsg+0x2be/0x4a0 net/socket.c:2917 ___sys_recvmsg+0x213/0x5a0 net/socket.c:2946 do_recvmmsg+0x31a/0x7f0 net/socket.c:3041 __sys_recvmmsg net/socket.c:3115 [inline] __do_sys_recvmmsg net/socket.c:3138 [inline] __se_sys_recvmmsg net/socket.c:3131 [inline] __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3131 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6fa299ce59 RSP: 002b:00007f6fa38bb028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f6fa2c16090 RCX: 00007f6fa299ce59 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f6fa2a32e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6fa2c16128 R14: 00007f6fa2c16090 R15: 00007f6fa2d3fa48 rcu: rcu_preempt kthread starved for 10412 jiffies! g688425 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: usb 1-1: pegasus_irq - nonzero urb status received: -71 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5720 Comm: kworker/0:8 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: wg-crypt-wg2 wg_packet_encrypt_worker RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401 Code: e8 6e 3c 7b fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ef c0 e8 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 1a 60 6b 06 cc 44 89 f9 80 e1 07 RSP: 0018:ffffc90000007318 EFLAGS: 00000006 RAX: 1ffffffff3500905 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000023e8b RDI: 0000000000023e8c RBP: ffffc900000074b0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff854b34c0 R12: dffffc0000000000 R13: ffffffff9a804dc0 R14: ffffffff9a804e00 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125226000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000001a9030 CR3: 0000000075334000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000041391c33 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: serial_port_in include/linux/serial_core.h:808 [inline] serial8250_console_write+0x503/0x1ba0 drivers/tty/serial/8250/8250_port.c:3343 console_emit_next_record kernel/printk/printk.c:3183 [inline] console_flush_one_record kernel/printk/printk.c:3269 [inline] console_flush_all+0x6ea/0xaf0 kernel/printk/printk.c:3343 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479 dev_vprintk_emit+0x338/0x400 drivers/base/core.c:4996 dev_printk_emit+0xee/0x140 drivers/base/core.c:5007 _dev_err+0x11e/0x180 drivers/base/core.c:5062 pegasus_irq+0x483/0x5a0 drivers/input/tablet/pegasus_notetaker.c:195 __usb_hcd_giveback_urb+0x374/0x530 drivers/usb/core/hcd.c:1657 dummy_timer+0xac3/0x4b40 drivers/usb/gadget/udc/dummy_hcd.c:2005 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2096 hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2113 handle_softirqs+0x225/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:skb_cow_data+0x13b/0xc50 net/core/skbuff.c:5373 Code: 04 28 84 c0 0f 85 16 0a 00 00 8b 03 49 8d 1c 06 48 83 c3 02 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 16 0a 00 00 0f b6 1b <31> ff 89 de e8 ec 98 45 f8 85 db 74 07 e8 e3 95 45 f8 eb 0f e8 dc RSP: 0018:ffffc9000525f530 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807e3abe00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888021a8f210 RBP: dffffc0000000000 R08: ffffc9000525f9ff R09: 0000000000000000 R10: ffffc9000525f6e0 R11: fffff52000a4bf40 R12: 0000000000000000 R13: ffff888021a8f140 R14: ffff88807d9123c0 R15: 0000000000000030 encrypt_packet drivers/net/wireguard/send.c:192 [inline] wg_packet_encrypt_worker+0x6e0/0x1760 drivers/net/wireguard/send.c:297 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - nonzero urb status received: -71 usb 1-1: pegasus_irq - usb_submit_urb failed with result -1