rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5024/1:b..l (detected by 0, t=10503 jiffies, g=13529, q=173) task:syz-executor.4 state:R running task stack:21544 pid: 5024 ppid: 5012 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6552 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6577 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 vprintk_emit+0x149/0x150 kernel/printk/printk.c:2275 dev_vprintk_emit+0x2cc/0x350 drivers/base/core.c:4638 dev_printk_emit+0xdd/0x120 drivers/base/core.c:4649 __netdev_printk+0x2ef/0x3d0 net/core/dev.c:11504 netdev_info+0x107/0x150 net/core/dev.c:11559 nsim_udp_tunnel_set_port+0x293/0x430 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+0x9d2/0x1320 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+0xb83/0xe80 net/ipv4/udp_tunnel_nic.c:531 udp_tunnel_nic_add_port include/net/udp_tunnel.h:336 [inline] udp_tunnel_notify_add_rx_port+0x260/0x3a0 net/ipv4/udp_tunnel_core.c:130 geneve_socket_create drivers/net/geneve.c:614 [inline] geneve_sock_add+0x53c/0x910 drivers/net/geneve.c:689 geneve_open+0xce/0x140 drivers/net/geneve.c:731 __dev_open+0x2b0/0x420 net/core/dev.c:1537 __dev_change_flags+0x20a/0x6a0 net/core/dev.c:8853 dev_change_flags+0x82/0x1a0 net/core/dev.c:8924 do_setlink+0xc01/0x3980 net/core/rtnetlink.c:2779 __rtnl_newlink net/core/rtnetlink.c:3450 [inline] rtnl_newlink+0x1419/0x17d0 net/core/rtnetlink.c:3572 rtnetlink_rcv_msg+0x9b9/0xe60 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2489 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x77c/0x920 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1905 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] __sys_sendto+0x423/0x580 net/socket.c:2063 __do_sys_sendto net/socket.c:2075 [inline] __se_sys_sendto net/socket.c:2071 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2071 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f551baadd9c RSP: 002b:00007ffef58b8560 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f551c713620 RCX: 00007f551baadd9c RDX: 000000000000002c RSI: 00007f551c713670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffef58b85b4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f551c713670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10559 jiffies! g13529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27848 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5370 Comm: syz-executor.1 Not tainted 5.15.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:__posix_timers_find kernel/time/posix-timers.c:124 [inline] RIP: 0010:posix_timer_by_id kernel/time/posix-timers.c:137 [inline] RIP: 0010:__lock_timer+0x120/0x3b0 kernel/time/posix-timers.c:631 Code: 31 f9 31 c1 69 c1 47 86 c8 61 c1 e8 17 48 8d 1c c5 60 69 0e 96 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 a6 f9 53 00 48 8b 1b 48 85 db 0f 94 c0 48 83 c3 RSP: 0018:ffffc90002e8fad0 EFLAGS: 00000046 RAX: 1ffffffff2c1cd91 RBX: ffffffff960e6c88 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffffff8a59a2a0 RDI: ffffffff8a59a260 RBP: ffff8880273aa6e0 R08: dffffc0000000000 R09: fffffbfff1ff3419 R10: fffffbfff1ff3419 R11: 1ffffffff1ff3418 R12: ffffc90002e8fb30 R13: 1ffff11004e754dc R14: ffff8880273aa6e0 R15: ffff888023281380 FS: 00007f732e2396c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f732e238d80 CR3: 000000006559d000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: posixtimer_rearm+0x5c/0x340 kernel/time/posix-timers.c:323 dequeue_signal+0x174/0x440 kernel/signal.c:696 get_signal+0x6fe/0x12c0 kernel/signal.c:2781 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f732eeb80a7 Code: 14 25 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 RSP: 002b:00007f732e239178 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f732efeef88 RCX: 00007f732eeb80a9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f732efeef88 RBP: 00007f732efeef80 R08: 00007f732e2396c0 R09: 00007f732e2396c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f732efeef8c R13: 000000000000000b R14: 00007fff555f5120 R15: 00007fff555f5208 sched: RT throttling activated