rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10275/1:b..l
(detected by 0, t=10502 jiffies, g=49953, q=334)
task:syz.6.1281 state:R running task stack:22624 pid:10275 ppid: 7436 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xbc/0xd0 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+0x2c2/0x360 drivers/base/core.c:4665
dev_printk_emit+0xeb/0x140 drivers/base/core.c:4676
__netdev_printk+0x2ef/0x3d0 net/core/dev.c:11530
netdev_info+0x11b/0x170 net/core/dev.c:11585
nsim_udp_tunnel_unset_port+0x2c4/0x520 drivers/net/netdevsim/udp_tunnels.c:64
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+0xa17/0x13c0 net/ipv4/udp_tunnel_nic.c:289
udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:312 [inline]
__udp_tunnel_nic_del_port+0x2ba/0x420 net/ipv4/udp_tunnel_nic.c:548
udp_tunnel_nic_del_port include/net/udp_tunnel.h:360 [inline]
udp_tunnel_notify_del_rx_port+0x266/0x3a0 net/ipv4/udp_tunnel_core.c:150
__geneve_sock_release drivers/net/geneve.c:636 [inline]
geneve_sock_release+0x37b/0x4a0 drivers/net/geneve.c:653
geneve_stop+0x172/0x1b0 drivers/net/geneve.c:746
__dev_close_many+0x1d3/0x2b0 net/core/dev.c:1634
__dev_close net/core/dev.c:1646 [inline]
__dev_change_flags+0x2c9/0x6a0 net/core/dev.c:8877
dev_change_flags+0x78/0x1a0 net/core/dev.c:8950
do_setlink+0xca4/0x29d0 net/core/rtnetlink.c:2793
__rtnl_newlink net/core/rtnetlink.c:3464 [inline]
rtnl_newlink+0x15bb/0x1920 net/core/rtnetlink.c:3586
rtnetlink_rcv_msg+0x7f1/0xf10 net/core/rtnetlink.c:5698
netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
__sys_sendmsg net/socket.c:2529 [inline]
__do_sys_sendmsg net/socket.c:2538 [inline]
__se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536
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: 0033:0x7f3d4cc49019
RSP: 002b:00007f3d4aea1028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3d4ced0fa0 RCX: 00007f3d4cc49019
RDX: 0000000002000000 RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f3d4cce000c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3d4ced1038 R14: 00007f3d4ced0fa0 R15: 00007fff9ef72a18
rcu: rcu_preempt kthread starved for 10462 jiffies! g49953 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:27856 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
kthread+0x42e/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 0
CPU: 0 PID: 10295 Comm: syz.0.1285 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 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+0x1110/0x1270 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+0x845/0x1120 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:2021
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+0x4b0/0xb60 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x397/0x8b0 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:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:227 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x61/0xe0 kernel/kcov.c:329
Code: 57 41 56 41 54 53 48 8d 4c 09 01 48 8b 54 24 20 65 4c 8b 05 61 6e 89 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 <65> 44 8b 1d 4f 6e 89 7e 41 81 e3 00 01 ff 00 74 13 41 81 fb 00 01
RSP: 0018:ffffc9000128f7f8 EFLAGS: 00000216
RAX: 0000000000000020 RBX: 0000007138a805c7 RCX: 0000000000000005
RDX: ffffffff817be86d RSI: ffffffff8c360560 RDI: 000000000000000a
RBP: 000000000000000a R08: ffff88802770d940 R09: 0000000000000005
R10: 0000000000000005 R11: 0000000000000002 R12: ffff88806582c068
R13: dffffc0000000000 R14: 0000000000000058 R15: 000000000007bb0a
check_buffer+0x23d/0x880 kernel/trace/ring_buffer.c:3452
__rb_reserve_next+0x4d9/0xd00 kernel/trace/ring_buffer.c:3581
rb_reserve_next_event kernel/trace/ring_buffer.c:3716 [inline]
ring_buffer_lock_reserve+0xadd/0xed0 kernel/trace/ring_buffer.c:3775
__trace_buffer_lock_reserve kernel/trace/trace.c:942 [inline]
trace_event_buffer_lock_reserve+0xd4/0x6a0 kernel/trace/trace.c:2819
trace_event_buffer_reserve+0x2a8/0x3d0 kernel/trace/trace_events.c:627
trace_event_raw_event_x86_fpu+0x11c/0x380 arch/x86/include/asm/trace/fpu.h:10
trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:57 [inline]
fpregs_activate+0x146/0x1a0 arch/x86/include/asm/fpu/internal.h:451
fpregs_mark_activate arch/x86/kernel/fpu/core.c:429 [inline]
fpu__clear_user_states+0x17d/0x260 arch/x86/kernel/fpu/core.c:387
handle_signal arch/x86/kernel/signal.c:840 [inline]
arch_do_signal_or_restart+0xeac/0x12a0 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: 0033:0x7f625fa2a590
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 72 2d 07 00 e8 65 65 f9 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:00007f625dc62b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f625fc92fa8 RCX: 00007f625fa0b019
RDX: 00007f625dc62b40 RSI: 00007f625dc62c70 RDI: 0000000000000021
RBP: 00007f625fc92fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f625fc93038 R14: 00007ffc4ace5050 R15: 00007ffc4ace5138