rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29563/3:b..l
rcu: (detected by 0, t=10503 jiffies, g=200501, q=1360010 ncpus=2)
task:syz.2.6327 state:R running task stack:25176 pid:29563 tgid:29556 ppid:24082 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7370
preempt_schedule_thunk+0x16/0x30 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]
ip6t_do_table+0xbfa/0x1c90 net/ipv6/netfilter/ip6_tables.c:375
ip6t_mangle_out net/ipv6/netfilter/ip6table_mangle.c:49 [inline]
ip6table_mangle_hook+0x31e/0x770 net/ipv6/netfilter/ip6table_mangle.c:72
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK include/linux/netfilter.h:316 [inline]
ip6_xmit+0x13cf/0x24a0 net/ipv6/ip6_output.c:379
inet6_csk_xmit+0x387/0x760 net/ipv6/inet6_connection_sock.c:115
__tcp_transmit_skb+0x1fab/0x4f10 net/ipv4/tcp_output.c:1715
tcp_transmit_skb net/ipv4/tcp_output.c:1733 [inline]
tcp_write_xmit+0x1136/0x8460 net/ipv4/tcp_output.c:3061
__tcp_push_pending_frames+0xaf/0x3b0 net/ipv4/tcp_output.c:3244
tcp_push_pending_frames include/net/tcp.h:2360 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:6075 [inline]
tcp_rcv_established+0x11e6/0x3910 net/ipv4/tcp_input.c:6558
tcp_v6_do_rcv+0x1129/0x1ff0 net/ipv6/tcp_ipv6.c:1610
sk_backlog_rcv include/net/sock.h:1190 [inline]
__release_sock+0x151/0x440 net/core/sock.c:3216
release_sock+0x1e5/0x280 net/core/sock.c:3815
sk_stream_wait_memory+0x651/0x10c0 net/core/stream.c:149
tcp_sendmsg_locked+0x158d/0x4500 net/ipv4/tcp.c:1405
tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1452
inet6_sendmsg+0xb9/0x140 net/ipv6/af_inet6.c:642
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
sock_write_iter+0x439/0x5a0 net/socket.c:1254
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1070 fs/read_write.c:688
ksys_write+0x1f8/0x250 fs/read_write.c:740
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: 0033:0x7fb228d9ce59
RSP: 002b:00007fb229cb9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb229016090 RCX: 00007fb228d9ce59
RDX: 00000000fffffd9d RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fb228e32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb229016128 R14: 00007fb229016090 R15: 00007fff56bf5a88
rcu: rcu_preempt kthread starved for 1653 jiffies! g200501 f0x2 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:27992 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lock_release+0x1b1/0x310 kernel/locking/lockdep.c:5893
Code: 58 f6 c4 02 0f 85 13 01 00 00 41 f7 c6 00 02 00 00 0f 85 c0 00 00 00 48 8b 44 24 10 65 48 2b 05 6d 1d 25 12 0f 85 4e 01 00 00 <48> 83 c4 18 5b 5d 41 5c 41 5e 41 5f c3 cc cc cc cc 65 8b 05 7b 1d
RSP: 0018:ffffc90000a08108 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8e7e5620 RCX: ffffc90000a08114
RDX: 0000000000000002 RSI: ffffffff8dee9983 RDI: ffffffff8c1c4480
RBP: ffffffff81b7c1ae R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000008efd0 R12: ffff88801e2b2540
R13: ffffc90000a081c0 R14: 0000000000000202 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff888124486000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f70f3b21f CR3: 00000000776d3000 CR4: 00000000003526f0
Call Trace:
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
__call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131
call_rcu_hurry include/linux/rcupdate.h:125 [inline]
dst_release net/core/dst.c:178 [inline]
dst_release+0x259/0x330 net/core/dst.c:166
refdst_drop include/net/dst.h:272 [inline]
skb_dst_drop include/net/dst.h:284 [inline]
skb_release_head_state+0x293/0x400 net/core/skbuff.c:1163
skb_release_all net/core/skbuff.c:1187 [inline]
__kfree_skb net/core/skbuff.c:1203 [inline]
consume_skb net/core/skbuff.c:1436 [inline]
consume_skb+0x8a/0x110 net/core/skbuff.c:1430
nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:61 [inline]
nft_synproxy_do_eval+0xa72/0xd50 net/netfilter/nft_synproxy.c:142
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x2e5/0x1990 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]
ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262
dst_input include/net/dst.h:480 [inline]
ip_rcv_finish net/ipv4/ip_input.c:492 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:612
__netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6202
__netif_receive_skb+0x1f/0x120 net/core/dev.c:6315
process_backlog+0x37a/0x1580 net/core/dev.c:6666
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7733
napi_poll net/core/dev.c:7796 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:7953
handle_softirqs+0x1ea/0xa00 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:1061 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: f5 92 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 03 51 22 00 fb f4 fc 43 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df0 EFLAGS: 00000246
RAX: 000000000b8fbcd7 RBX: ffff88801e2b2540 RCX: ffffffff8b894285
RDX: 0000000000000000 RSI: ffffffff8df0eee6 RDI: ffffffff8c1c4480
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a67b5
R10: ffff8880b8533dab R11: 0000000000000000 R12: 0000000000000001
R13: ffffed1003c564a8 R14: 0000000000000001 R15: ffffffff90d70550
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x464/0x590 kernel/sched/idle.c:352
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x148