rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8504/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=38189, q=2148 ncpus=2)
task:syz.1.739 state:R running task stack:26576 pid:8504 tgid:8501 ppid:5843 task_flags:0x400140 flags:0x10080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:747 [inline]
RIP: 0010:rcu_is_watching+0x6/0xb0 kernel/rcu/tree.c:750
Code: e8 9f fa 1f 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 <41> 56 53 65 ff 05 00 13 d9 10 e8 6b de b2 09 89 c3 83 f8 08 73 65
RSP: 0018:ffffc900031b71c8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff90166301 RCX: ffff88802b5bbd00
RDX: ffffc900031b7201 RSI: dffffc0000000000 RDI: ffffc900031b72b0
RBP: dffffc0000000000 R08: ffffc900031b7d30 R09: 0000000000000000
R10: ffffc900031b72f8 R11: fffff52000636e61 R12: ffffc900031b7d40
R13: ffffc900031b0000 R14: ffffc900031b72a8 R15: ffffffff8173fd65
rcu_read_unlock include/linux/rcupdate.h:895 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x1a6d/0x23d0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x146/0x170 mm/slub.c:3886
__slab_free+0x294/0x320 mm/slub.c:5952
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
vm_area_dup+0x2b/0x680 mm/vma_init.c:123
dup_mmap+0x870/0x1b80 mm/mmap.c:1773
dup_mm kernel/fork.c:1529 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1581
copy_process+0x165d/0x3950 kernel/fork.c:2221
kernel_clone+0x21e/0x820 kernel/fork.c:2651
__do_compat_sys_ia32_clone arch/x86/kernel/sys_ia32.c:254 [inline]
__se_compat_sys_ia32_clone arch/x86/kernel/sys_ia32.c:240 [inline]
__ia32_compat_sys_ia32_clone+0x189/0x1e0 arch/x86/kernel/sys_ia32.c:240
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0x1dc/0x570 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf705d539
RSP: 002b:00000000f540b50c EFLAGS: 00000206 ORIG_RAX: 0000000000000078
RAX: ffffffffffffffda RBX: 0000000000100011 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 901 jiffies! g38189 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:27480 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 838 Comm: kworker/1:2 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: wg-kex-wg0 wg_packet_handshake_receive_worker
RIP: 0010:fib6_table_lookup+0xc/0xa80 net/ipv6/route.c:2237
Code: 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 <41> 55 41 54 53 48 83 e4 e0 48 81 ec 40 01 00 00 4c 89 4c 24 30 4d
RSP: 0018:ffffc90000a07e00 EFLAGS: 00000246
RAX: ffffffff8a0ab91f RBX: 0000000000000003 RCX: ffffc90000a081a0
RDX: 0000000000000000 RSI: ffff88807edd4000 RDI: ffff8880328b0000
RBP: ffffc90000a07e10 R08: ffffc90000a07e90 R09: 0000000000000003
R10: ffffc90000a07e90 R11: fffff52000140fd6 R12: ffffc90000a081a0
R13: ffffc90000a07e90 R14: ffff8880328b0000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000ef5edff0 CR3: 000000005e87e000 CR4: 00000000003526f0
Call Trace:
ip6_pol_route+0x22c/0x11a0 net/ipv6/route.c:2280
pol_lookup_func include/net/ip6_fib.h:617 [inline]
fib6_rule_lookup+0x1fc/0x6f0 net/ipv6/fib6_rules.c:120
ip6_route_output_flags_noref net/ipv6/route.c:2695 [inline]
ip6_route_output_flags+0x364/0x5d0 net/ipv6/route.c:2707
ip6_route_output include/net/ip6_route.h:93 [inline]
__nf_ip6_route+0x42/0xd0 net/ipv6/netfilter.c:116
nf_ip6_route include/linux/netfilter_ipv6.h:111 [inline]
synproxy_send_tcp_ipv6+0x252/0x700 net/netfilter/nf_synproxy_core.c:835
synproxy_send_client_synack_ipv6+0x80e/0xca0 net/netfilter/nf_synproxy_core.c:897
nft_synproxy_eval_v6+0x33a/0x4d0 net/netfilter/nft_synproxy.c:90
nft_synproxy_do_eval+0x3d7/0x570 net/netfilter/nft_synproxy.c:145
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6139 [inline]
__netif_receive_skb+0xd3/0x380 net/core/dev.c:6252
process_backlog+0x54f/0x1340 net/core/dev.c:6604
__napi_poll+0xae/0x320 net/core/dev.c:7668
napi_poll net/core/dev.c:7731 [inline]
net_rx_action+0x64a/0xe00 net/core/dev.c:7883
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
blake2s_compress+0xe0/0x1e30 lib/crypto/x86/blake2s.h:42
blake2s_update+0x14b/0x450 lib/crypto/blake2s.c:119
blake2s include/crypto/blake2s.h:156 [inline]
compute_mac1+0x145/0x1a0 drivers/net/wireguard/cookie.c:80
wg_cookie_validate_packet+0x129/0x320 drivers/net/wireguard/cookie.c:130
wg_receive_handshake_packet drivers/net/wireguard/receive.c:121 [inline]
wg_packet_handshake_receive_worker+0x476/0xfc0 drivers/net/wireguard/receive.c:213
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246