rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10057/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=121121, q=3517 ncpus=2)
task:syz.2.11075 state:R running task stack:22904 pid:10057 tgid:10057 ppid:5786 task_flags:0x40064c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7228
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7552
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:debug_lockdep_rcu_enabled+0x2b/0x40 kernel/rcu/update.c:320
Code: 0f 1e fa 8b 05 6e 23 40 05 85 c0 74 20 8b 05 20 56 40 05 85 c0 74 16 65 48 8b 05 c8 2d 78 08 8b 80 9c 0b 00 00 85 c0 0f 94 c0 <0f> b6 c0 e9 3d 3f 03 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90
RSP: 0000:ffffc90005d071b8 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffea00024c2340 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8df33a7e RDI: ffffffff8c1e7180
RBP: 00000000000000ff R08: 00000000ffffffff R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: ffffea00024c2368
R13: ffffea00024c2340 R14: 0000000000000000 R15: dffffc0000000000
rcu_read_lock include/linux/rcupdate.h:841 [inline]
__page_table_check_zero+0x91/0x410 mm/page_table_check.c:138
page_table_check_free include/linux/page_table_check.h:46 [inline]
__free_pages_prepare mm/page_alloc.c:1407 [inline]
free_unref_folios+0xa35/0x1710 mm/page_alloc.c:3011
folios_put_refs+0x585/0xaa0 mm/swap.c:1057
folio_batch_release include/linux/folio_batch.h:101 [inline]
shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1149
shmem_truncate_range mm/shmem.c:1277 [inline]
shmem_evict_inode+0x3a5/0xbe0 mm/shmem.c:1407
evict+0x3c2/0xad0 fs/inode.c:825
iput_final fs/inode.c:2019 [inline]
iput.part.0+0x989/0x1050 fs/inode.c:2068
iput+0x35/0x40 fs/inode.c:2034
dentry_unlink_inode+0x284/0x470 fs/dcache.c:479
dentry_kill+0x25d/0xc20 fs/dcache.c:826
finish_dput fs/dcache.c:1001 [inline]
dput.part.0+0xd7/0x240 fs/dcache.c:1042
dput+0x1f/0x30 fs/dcache.c:1037
__fput+0x519/0xb50 fs/file_table.c:520
task_work_run+0x150/0x240 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x951/0x2ae0 kernel/exit.c:1004
do_group_exit+0xd5/0x2a0 kernel/exit.c:1147
get_signal+0x1ec7/0x21e0 kernel/signal.c:3038
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
irqentry_exit+0x402/0xa00 kernel/entry/common.c:165
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x7fd3a919ce59
RSP: 002b:fffffffffffffc70 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 00007fd3a9415fa0 RCX: 00007fd3a919ce59
RDX: 0000000000000000 RSI: fffffffffffffc70 RDI: 0000000001022000
RBP: 00007fd3a9232e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fd3a9416038 R14: 00007fd3a9415fa0 R15: 00007ffead2f3608
rcu: rcu_preempt kthread starved for 1820 jiffies! g121121 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:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7322
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:
CPU: 0 UID: 0 PID: 6040 Comm: kworker/0:7 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:rps_input_queue_tail_save include/net/rps.h:181 [inline]
RIP: 0010:enqueue_to_backlog+0x35d/0x1130 net/core/dev.c:5414
Code: f8 48 85 db 0f 85 12 04 00 00 e8 8e 46 9a f8 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 1c 41 9a f8 48 85 db 0f 85 9b 0a 00 00 6e 46 9a f8 48 8b 4c 24 08 48 b8 00 00 00 00 00 fc ff df 48 89
RSP: 0018:ffffc90000006da8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff896f3cfb
RDX: ffff888026568000 RSI: ffffffff896f3d09 RDI: ffff888026568000
RBP: 00000000001850b9 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d0335dc0
R13: ffff8880b843d2a0 R14: ffff8880b843d2b0 R15: ffffffff94156080
FS: 0000000000000000(0000) GS:ffff8881242e7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0c47a00000 CR3: 000000002faf8000 CR4: 00000000003526f0
Call Trace:
netif_rx_internal+0x102/0x600 net/core/dev.c:5723
__netif_rx+0x88/0xb0 net/core/dev.c:5743
loopback_xmit+0x284/0x6e0 drivers/net/loopback.c:90
__netdev_start_xmit include/linux/netdevice.h:5387 [inline]
netdev_start_xmit include/linux/netdevice.h:5396 [inline]
xmit_one net/core/dev.c:3889 [inline]
dev_hard_start_xmit+0x121/0x760 net/core/dev.c:3905
__dev_queue_xmit+0x1b9d/0x4940 net/core/dev.c:4872
dev_queue_xmit include/linux/netdevice.h:3436 [inline]
neigh_hh_output include/net/neighbour.h:544 [inline]
neigh_output include/net/neighbour.h:558 [inline]
ip6_finish_output2+0xfd4/0x1ce0 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]
ip6_local_out+0xcb/0x1f0 net/ipv6/output_core.c:128
synproxy_send_tcp_ipv6+0x5f3/0x700 net/netfilter/nf_synproxy_core.c:861
synproxy_send_client_synack_ipv6+0x601/0x7a0 net/netfilter/nf_synproxy_core.c:907
nft_synproxy_eval_v6 net/netfilter/nft_synproxy.c:91 [inline]
nft_synproxy_do_eval+0x938/0xd50 net/netfilter/nft_synproxy.c:146
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x2e5/0x19d0 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0xf3/0x400 net/netfilter/nft_chain_filter.c:162
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619
nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273
NF_HOOK include/linux/netfilter.h:316 [inline]
ip6_input+0xe0/0x2f0 net/ipv6/ip6_input.c:545
dst_input include/net/dst.h:480 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:119 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ipv6_rcv+0x263/0x3d0 net/ipv6/ip6_input.c:351
__netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6206
__netif_receive_skb+0x1f/0x120 net/core/dev.c:6319
process_backlog+0x37a/0x1580 net/core/dev.c:6670
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7729
napi_poll net/core/dev.c:7792 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:7949
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
do_softirq kernel/softirq.c:523 [inline]
do_softirq+0xac/0xe0 kernel/softirq.c:510
__local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
spin_unlock_bh include/linux/spinlock.h:396 [inline]
neigh_periodic_work+0x6da/0xc10 net/core/neighbour.c:1035
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
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