rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5649/1:b..l P15097/1:b..l P15044/2:b..l
rcu: (detected by 0, t=10503 jiffies, g=136945, q=888126 ncpus=2)
task:syz.1.2632 state:R running task stack:21736 pid:15044 tgid:15043 ppid:5649 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457
local_bh_enable include/linux/bottom_half.h:33 [inline]
ipt_do_table+0x13d2/0x1630 net/ipv4/netfilter/ip_tables.c:357
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook+0x22a/0x3a0 include/linux/netfilter.h:273
__ip_local_out+0x558/0x6a0 net/ipv4/ip_output.c:120
ip_local_out+0x2a/0x190 net/ipv4/ip_output.c:129
__ip_queue_xmit+0x116a/0x1bb0 net/ipv4/ip_output.c:534
__tcp_transmit_skb+0x2d76/0x4790 net/ipv4/tcp_output.c:1715
tcp_transmit_skb net/ipv4/tcp_output.c:1733 [inline]
tcp_write_xmit+0x1be0/0x6540 net/ipv4/tcp_output.c:3060
__tcp_push_pending_frames+0x97/0x380 net/ipv4/tcp_output.c:3243
tcp_push_pending_frames include/net/tcp.h:2359 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:6075 [inline]
tcp_rcv_established+0x1019/0x2800 net/ipv4/tcp_input.c:6658
tcp_v4_do_rcv+0x903/0x13c0 net/ipv4/tcp_ipv4.c:1851
sk_backlog_rcv include/net/sock.h:1190 [inline]
__release_sock+0x265/0x3a0 net/core/sock.c:3216
__sk_flush_backlog+0x36/0xc0 net/core/sock.c:3239
sk_flush_backlog include/net/sock.h:1253 [inline]
tcp_sendmsg_locked+0x4161/0x5360 net/ipv4/tcp.c:1256
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1455
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
__sys_sendto+0x5de/0x710 net/socket.c:2265
__do_sys_sendto net/socket.c:2272 [inline]
__se_sys_sendto net/socket.c:2268 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2268
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fde2879ce59
RSP: 002b:00007fde2969f028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fde28a15fa0 RCX: 00007fde2879ce59
RDX: ffffffffffffff94 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007fde28832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fde28a16038 R14: 00007fde28a15fa0 R15: 00007fde28b3fa48
task:syz.6.2645 state:R running task stack:26840 pid:15097 tgid:15092 ppid:12700 task_flags:0x40044c flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190
spin_unlock include/linux/spinlock.h:390 [inline]
zap_pte_range mm/memory.c:1948 [inline]
zap_pmd_range mm/memory.c:2004 [inline]
zap_pud_range mm/memory.c:2032 [inline]
zap_p4d_range mm/memory.c:2053 [inline]
__zap_vma_range+0x3d17/0x4b40 mm/memory.c:2093
unmap_vmas+0x379/0x530 mm/memory.c:2162
exit_mmap+0x280/0x9e0 mm/mmap.c:1300
__mmput+0x118/0x430 kernel/fork.c:1178
exit_mm+0x1f6/0x2d0 kernel/exit.c:582
do_exit+0x6a2/0x22c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1119
get_signal+0x1284/0x1330 kernel/signal.c:3037
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f128a99ce59
RSP: 002b:00007f128b8da028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 000000000000000b RBX: 00007f128ac15fa0 RCX: 00007f128a99ce59
RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000005
RBP: 00007f128aa32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f128ac16038 R14: 00007f128ac15fa0 R15: 00007f128ad3fa48
task:syz-executor state:R running task stack:21408 pid:5649 tgid:5649 ppid:1 task_flags:0x40054c flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190
spin_unlock include/linux/spinlock.h:390 [inline]
zap_pte_range mm/memory.c:1948 [inline]
zap_pmd_range mm/memory.c:2004 [inline]
zap_pud_range mm/memory.c:2032 [inline]
zap_p4d_range mm/memory.c:2053 [inline]
__zap_vma_range+0x3d17/0x4b40 mm/memory.c:2093
unmap_vmas+0x379/0x530 mm/memory.c:2162
exit_mmap+0x280/0x9e0 mm/mmap.c:1300
__mmput+0x118/0x430 kernel/fork.c:1178
exit_mm+0x1f6/0x2d0 kernel/exit.c:582
do_exit+0x6a2/0x22c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1119
get_signal+0x1284/0x1330 kernel/signal.c:3037
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fde2875d68e
RSP: 002b:00007fde28b3fd48 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 0000555591b9e500 RCX: 00007fde2875d68e
RDX: 0000000040000000 RSI: 00007fde28b3fdec RDI: ffffffffffffffff
RBP: 00007fde28b3fdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000210
R13: 0000555591bb1a00 R14: 00000000000aff7c R15: 00007fde28b3fe40
rcu: rcu_preempt kthread starved for 3919 jiffies! g136945 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 11111 Comm: kworker/u8:13 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:unwind_next_frame+0x6eb/0x2550 arch/x86/kernel/unwind_orc.c:527
Code: 00 00 41 c6 07 01 48 c7 c2 60 f6 7b 8e 4c 8b 6c 24 20 48 8d 72 04 4c 8d 62 05 48 89 f0 48 c1 e8 03 48 89 44 24 48 0f b6 04 28 <84> c0 48 89 14 24 48 89 74 24 08 0f 85 9e 17 00 00 4c 89 e0 48 c1
RSP: 0018:ffffc90000a077b8 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffffffff90a84bd0 RCX: ffffffff90a84bd8
RDX: ffffffff91539aaa RSI: ffffffff91539aae RDI: ffffffff8c28b080
RBP: dffffc0000000000 R08: 000000000000000c R09: ffffffff8e95cca0
R10: ffffc90000a078d8 R11: ffffffff81b0eff0 R12: ffffffff91539aaf
R13: 1ffff92000140f11 R14: ffffc90000a07888 R15: ffffffff8176f256
FS: 0000000000000000(0000) GS:ffff88812538a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f49a23e01d4 CR3: 000000000e74a000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5419
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
ref_tracker_alloc+0x15a/0x4c0 lib/ref_tracker.c:270
__netdev_tracker_alloc include/linux/netdevice.h:4471 [inline]
netdev_hold include/linux/netdevice.h:4500 [inline]
dst_init+0xd9/0x480 net/core/dst.c:52
dst_alloc+0x12a/0x170 net/core/dst.c:94
rt_dst_alloc net/ipv4/route.c:1651 [inline]
__mkroute_output net/ipv4/route.c:2655 [inline]
ip_route_output_key_hash_rcu+0x14d0/0x25d0 net/ipv4/route.c:2875
ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2705
__ip_route_output_key include/net/route.h:169 [inline]
ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2932
ip_route_output_key include/net/route.h:179 [inline]
ip_route_me_harder+0x742/0xf90 net/ipv4/netfilter.c:54
synproxy_send_tcp+0x34c/0x670 net/netfilter/nf_synproxy_core.c:432
synproxy_send_client_synack+0x8c1/0xe30 net/netfilter/nf_synproxy_core.c:485
nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60
nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6202 [inline]
__netif_receive_skb net/core/dev.c:6315 [inline]
process_backlog+0xaa3/0x1950 net/core/dev.c:6666
__napi_poll+0xae/0x340 net/core/dev.c:7733
napi_poll net/core/dev.c:7796 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7953
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xfd4/0x13d0 kernel/smp.c:892
Code: 89 ee 83 e6 01 31 ff e8 7a 06 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 25 02 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 0a 02 0c 00 eb e5 44 89
RSP: 0018:ffffc9000d697700 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b873c148 RCX: ffff88802cea1ec0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000d697840 R08: ffffffff9030c4f7 R09: 1ffffffff206189e
R10: dffffc0000000000 R11: fffffbfff206189f R12: 1ffff110170c8589
R13: dffffc0000000000 R14: ffff8880b8642c48 R15: 0000000000000000
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057
on_each_cpu include/linux/smp.h:72 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:906
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245