rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13771/3:b..l
rcu: (detected by 1, t=10503 jiffies, g=86441, q=588 ncpus=2)
task:syz.4.2105 state:R running task stack:22496 pid:13771 tgid:13766 ppid:5614 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
__local_bh_enable_ip+0xff/0x120 kernel/softirq.c:457
local_bh_enable include/linux/bottom_half.h:33 [inline]
__neigh_event_send+0x331/0x13d0 net/core/neighbour.c:1276
neigh_event_send_probe include/net/neighbour.h:480 [inline]
neigh_event_send include/net/neighbour.h:486 [inline]
neigh_event_send include/net/neighbour.h:484 [inline]
neigh_resolve_output+0x550/0x8f0 net/core/neighbour.c:1600
neigh_output include/net/neighbour.h:560 [inline]
ip6_finish_output2+0xb0f/0x1ce0 net/ipv6/ip6_output.c:136
__ip6_finish_output+0x357/0xdf0 net/ipv6/ip6_output.c:208
ip6_finish_output net/ipv6/ip6_output.c:219 [inline]
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x2aa/0xa60 net/ipv6/ip6_output.c:246
dst_output include/net/dst.h:470 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ip6_xmit+0x1006/0x24a0 net/ipv6/ip6_output.c:379
inet6_csk_xmit+0x387/0x760 net/ipv6/inet6_connection_sock.c:121
__tcp_transmit_skb+0x1fb2/0x4f20 net/ipv4/tcp_output.c:1716
tcp_transmit_skb net/ipv4/tcp_output.c:1734 [inline]
tcp_connect+0x3704/0x5510 net/ipv4/tcp_output.c:4379
tcp_v6_connect+0x1831/0x2660 net/ipv6/tcp_ipv6.c:346
__inet_stream_connect+0x208/0xfa0 net/ipv4/af_inet.c:684
inet_stream_connect+0x57/0xa0 net/ipv4/af_inet.c:755
__sys_connect_file+0x141/0x1a0 net/socket.c:2135
__sys_connect+0x141/0x170 net/socket.c:2154
__do_sys_connect net/socket.c:2160 [inline]
__se_sys_connect net/socket.c:2157 [inline]
__x64_sys_connect+0x72/0xb0 net/socket.c:2157
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f65e979de59
RSP: 002b:00007f65ea63e028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f65e9a26180 RCX: 00007f65e979de59
RDX: 000000000000001c RSI: 0000200000000180 RDI: 0000000000000009
RBP: 00007f65e9833e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f65e9a26218 R14: 00007f65e9a26180 R15: 00007ffd4539ec78
rcu: rcu_preempt kthread starved for 9670 jiffies! g86441 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:27592 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
RIP: 0010:check_preemption_disabled+0x2/0xe0 lib/smp_processor_id.c:13
Code: 0f 65 8b 05 fc 67 aa 08 85 c0 74 04 90 0f 0b 90 e9 53 fc ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 54 <55> 53 48 83 ec 08 65 8b 1d d5 25 aa 08 65 f7 05 c6 25 aa 08 ff ff
RSP: 0018:ffffc90000007da0 EFLAGS: 00000046
RAX: 0000000000000002 RBX: ffffffff8ebe6100 RCX: ffffc90000007dbc
RDX: 0000000000000002 RSI: ffffffff8e17d446 RDI: ffffffff8c400c80
RBP: ffffffff89c6e1dc R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8e891480
R13: 0000000000000000 R14: 0000000000000202 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff888123deb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f3cb3c0ff0 CR3: 0000000032814000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
lock_release kernel/locking/lockdep.c:5891 [inline]
lock_release+0x170/0x310 kernel/locking/lockdep.c:5875
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
taprio_dequeue+0x161/0x5f0 net/sched/sch_taprio.c:867
dequeue_skb net/sched/sch_generic.c:322 [inline]
qdisc_restart net/sched/sch_generic.c:427 [inline]
__qdisc_run+0x1be/0x1b20 net/sched/sch_generic.c:445
qdisc_run include/net/pkt_sched.h:120 [inline]
qdisc_run include/net/pkt_sched.h:117 [inline]
net_tx_action+0x549/0xf50 net/core/dev.c:5857
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 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+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: a6 8d 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 79 12 00 fb f4 bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e807e10 EFLAGS: 00000242
RAX: 0000000004f799d5 RBX: ffffffff8e891480 RCX: ffffffff8bb922d5
RDX: 0000000000000000 RSI: ffffffff8e1a3122 RDI: ffffffff8c400c80
RBP: fffffbfff1d12290 R08: 0000000000000001 R09: ffffed101708678d
R10: ffff8880b8433c6b R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffffffff1d00fc6 R15: dffffc0000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:768
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
rest_init+0x251/0x260 init/main.c:717
start_kernel+0x48e/0x490 init/main.c:1175
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x158