rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4964/1:b..l
(detected by 1, t=10502 jiffies, g=11553, q=177)
task:syz-executor state:R running task stack:21952 pid: 4964 ppid: 4957 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:preempt_schedule_common+0xc4/0xd0 kernel/sched/core.c:6580
Code: df be 08 00 00 00 e8 db 0c 12 f8 48 89 d8 48 c1 e8 03 42 80 3c 38 00 0f 84 5a ff ff ff 48 89 df e8 31 0b 12 f8 e9 4d ff ff ff <5b> 41 5e 41 5f c3 66 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 53 48
RSP: 0018:ffffc9000342e100 EFLAGS: 00000246
RAX: 1ffff1100ba2d3b8 RBX: ffff88805d169dc0 RCX: ffffffff89aa2965
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88805d169dc0
RBP: ffffc9000342e198 R08: dffffc0000000000 R09: ffffed100ba2d3b9
R10: ffffed100ba2d3b9 R11: 1ffff1100ba2d3b8 R12: ffffc9000342e280
R13: 0000000000000000 R14: ffff88805d16b2a8 R15: dffffc0000000000
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
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:2781
__rtnl_newlink net/core/rtnetlink.c:3452 [inline]
rtnl_newlink+0x1419/0x17d0 net/core/rtnetlink.c:3574
rtnetlink_rcv_msg+0x7ff/0xe90 net/core/rtnetlink.c:5684
netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
__sys_sendto+0x423/0x580 net/socket.c:2073
__do_sys_sendto net/socket.c:2085 [inline]
__se_sys_sendto net/socket.c:2081 [inline]
__x64_sys_sendto+0xda/0xf0 net/socket.c:2081
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: 0033:0x7f9fc84cca3c
RSP: 002b:00007ffec9a7ea50 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f9fc9240620 RCX: 00007f9fc84cca3c
RDX: 000000000000002c RSI: 00007f9fc9240670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffec9a7eaa4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f9fc9240670 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10573 jiffies! g11553 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:28064 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
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:
NMI backtrace for cpu 1
CPU: 1 PID: 5558 Comm: syz.1.156 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be 2b b1 f7 48 89 df e8 86 00 b2 f7 e8 21 9a d2 f7 fb bf 01 00 00 00 56 22 a6 f7 65 8b 05 e7 1f 57 76 85 c0 74 02 5b c3 e8 f4 2a 55
RSP: 0018:ffffc9000150fb50 EFLAGS: 00000282
RAX: b44c44a73995c800 RBX: ffff8880726a1280 RCX: b44c44a73995c800
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: 0000000000000001
RBP: ffffc9000150fcb0 R08: dffffc0000000000 R09: ffffed100e4d4251
R10: ffffed100e4d4251 R11: 1ffff1100e4d4250 R12: dffffc0000000000
R13: 0000000100000000 R14: 0000000000000000 R15: 0000000000000020
set_current_blocked kernel/signal.c:3072 [inline]
signal_delivered kernel/signal.c:2936 [inline]
signal_setup_done+0x28c/0x440 kernel/signal.c:2947
handle_signal arch/x86/kernel/signal.c:842 [inline]
arch_do_signal_or_restart+0xf2e/0x1300 arch/x86/kernel/signal.c:869
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+0xee/0x180 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: 0033:0x7f4a370e12e0
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 6a 3e 08 00 e8 25 90 f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007f4a36727b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f4a372fffa8 RCX: 00007f4a370b8ba9
RDX: 00007f4a36727b40 RSI: 00007f4a36727c70 RDI: 0000000000000021
RBP: 00007f4a372fffa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4a37300038 R14: 00007ffe4d8d31a0 R15: 00007ffe4d8d3288
sched: RT throttling activated