rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5906/1:b..l rcu: (detected by 1, t=10503 jiffies, g=10225, q=672 ncpus=2) task:syz-executor state:R running task stack:21736 pid:5906 ppid:5904 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 vprintk_emit+0x578/0x600 kernel/printk/printk.c:2342 dev_vprintk_emit+0x338/0x3e0 drivers/base/core.c:4953 dev_printk_emit+0xe1/0x130 drivers/base/core.c:4964 __netdev_printk+0x3bf/0x4a0 net/core/dev.c:11482 netdev_info+0x10b/0x160 net/core/dev.c:11537 nsim_udp_tunnel_set_port+0x297/0x440 drivers/net/netdevsim/udp_tunnels.c:34 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline] udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline] __udp_tunnel_nic_device_sync+0xa70/0x1370 net/ipv4/udp_tunnel_nic.c:289 udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:312 [inline] __udp_tunnel_nic_add_port+0xaf8/0xdb0 net/ipv4/udp_tunnel_nic.c:531 udp_tunnel_nic_add_port include/net/udp_tunnel.h:333 [inline] udp_tunnel_notify_add_rx_port+0x28e/0x3e0 net/ipv4/udp_tunnel_core.c:127 geneve_socket_create drivers/net/geneve.c:614 [inline] geneve_sock_add+0x55e/0x910 drivers/net/geneve.c:689 geneve_open+0xd2/0x140 drivers/net/geneve.c:731 __dev_open+0x2bc/0x430 net/core/dev.c:1506 __dev_change_flags+0x20e/0x6a0 net/core/dev.c:8685 dev_change_flags+0x88/0x1a0 net/core/dev.c:8757 do_setlink+0xc74/0x3fb0 net/core/rtnetlink.c:2905 __rtnl_newlink net/core/rtnetlink.c:3703 [inline] rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6472 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f7a9259155c RSP: 002b:00007ffce9ac50d0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f7a93314620 RCX: 00007f7a9259155c RDX: 000000000000002c RSI: 00007f7a93314670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffce9ac5124 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f7a93314670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10498 jiffies! g10225 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:27272 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:destroy_timer_on_stack kernel/time/timer.c:812 [inline] RIP: 0010:schedule_timeout+0x16a/0x280 kernel/time/timer.c:2171 Code: 6a 00 e8 29 76 ee f6 48 83 c4 08 4c 89 f7 48 89 de ba 04 00 00 00 e8 b5 b6 fc f6 e8 30 b3 fe ff 4c 89 f7 31 f6 e8 a6 d1 fc f6 <4c> 89 f7 48 c7 c6 00 9f ac 8a e8 e7 c4 ad f9 43 80 7c 3d 00 00 74 RSP: 0018:ffffc90000167b80 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000ffffad0c RCX: ffff88801b270000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000167c70 R08: ffffffff8e4a8d6f R09: 1ffffffff1c951ad R10: dffffc0000000000 R11: fffffbfff1c951ae R12: 1ffff9200002cf70 R13: 1ffffffff1941e40 R14: ffffc90000167ba0 R15: dffffc0000000000 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6178 Comm: syz.2.100 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:trace_irq_enable+0x30/0xe0 include/trace/events/preemptirq.h:40 Code: 8b 05 00 c6 77 7e 83 f8 08 73 2e 89 c3 c1 e8 06 48 8d 3c c5 68 8d 4a 8e be 08 00 00 00 e8 b8 fa 50 00 48 0f a3 1d 78 9b be 0c <73> 09 e8 59 a7 e3 ff 84 c0 74 08 5b 41 5e c3 0f 0b eb ce 0f 0b eb RSP: 0018:ffffc900045bfee8 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff818bf1e8 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a8d68 RBP: ffffc900045bff48 R08: ffffffff8e4a8d6f R09: 1ffffffff1c951ad R10: dffffc0000000000 R11: fffffbfff1c951ae R12: 0000000000000000 R13: 0000000000000000 R14: ffffc900045bff58 R15: 0000000000000000 FS: 00007f9fd01db6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 000000007729a000 CR4: 00000000003506f0 Call Trace: trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56 syscall_enter_from_user_mode+0x25/0x80 kernel/entry/common.c:117 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9fcf386567 Code: 0b e9 68 fe ff ff 48 83 c4 18 48 8d 3d 32 63 d9 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 f3 f7 fb ff 0f 1f 00 b8 27 00 00 00 0f 05 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007f9fd01dab08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: ffffffffffffffda RBX: 00007f9fd01dac70 RCX: 00007f9fcf386567 RDX: 00007f9fd01dab40 RSI: 00007f9fd01dac70 RDI: 0000000000000021 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007f9fcf5e6038 R14: 00007ffc676628e0 R15: 00007ffc676629c8 sched: RT throttling activated