rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5614/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=33201, q=940688 ncpus=2)
task:syz-executor state:R running task stack:21216 pid:5614 tgid:5614 ppid:5603 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7506
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753
trace_lock_acquire include/trace/events/lock.h:23 [inline]
lock_acquire+0x5f/0x350 kernel/locking/lockdep.c:5831
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 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+0xc1e/0xd10 mm/page_alloc.c:2950
__slab_free+0x274/0x2c0 mm/slub.c:5741
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5334 [inline]
__kmalloc_noprof+0x375/0x720 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
tomoyo_encode+0x2ad/0x570 security/tomoyo/realpath.c:80
tomoyo_realpath_from_path+0x5fa/0x640 security/tomoyo/realpath.c:283
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827
security_inode_getattr+0x12b/0x310 security/security.c:1895
vfs_getattr fs/stat.c:259 [inline]
vfs_fstat fs/stat.c:281 [inline]
__do_sys_newfstat fs/stat.c:551 [inline]
__se_sys_newfstat fs/stat.c:546 [inline]
__x64_sys_newfstat+0x133/0x270 fs/stat.c:546
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7a04b9c6e7
RSP: 002b:00007fff37837348 EFLAGS: 00000206 ORIG_RAX: 0000000000000005
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f7a04b9c6e7
RDX: 0000000000000000 RSI: 00007fff37837350 RDI: 0000000000000003
RBP: 00007fff3783853c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007fff37838550
R13: 00007f7a04c34474 R14: 000000000003202e R15: 00007fff37838590
rcu: rcu_preempt kthread starved for 624 jiffies! g33201 f0x2 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
kthread+0x388/0x470 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6306 Comm: kworker/u8:16 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:222 [inline]
RIP: 0010:unwind_next_frame+0x1d6/0x2550 arch/x86/kernel/unwind_orc.c:510
Code: fd 48 35 d5 8b 0f 93 c1 08 c1 0f 85 0b 01 00 00 48 c7 c0 00 00 00 81 49 89 ef 49 29 c7 49 c1 ef 08 8b 15 7d 29 d8 0c 8d 42 ff <44> 39 f8 0f 86 6c 04 00 00 44 89 f8 4c 8d 2c 85 f8 43 9d 91 4c 89
RSP: 0018:ffffc90000006660 EFLAGS: 00000202
RAX: 00000000000ad536 RBX: 0000000000000001 RCX: 0000000000000300
RDX: 00000000000ad537 RSI: ffffffff8c4bba60 RDI: ffffffff8c4bba20
RBP: ffffffff816c5703 R08: ffffffff8177827f R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8eb59c60 R12: dffffc0000000000
R13: ffffffff8177827f R14: ffffc90000006708 R15: 0000000000006c57
FS: 0000000000000000(0000) GS:ffff888124f58000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ce8ff14b8 CR3: 000000000e946000 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
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6504
kfree_skb_reason include/linux/skbuff.h:1323 [inline]
enqueue_to_backlog+0x68c/0xef0 net/core/dev.c:5460
netif_rx_internal+0x120/0x550 net/core/dev.c:5758
__netif_rx+0x78/0xc0 net/core/dev.c:5778
loopback_xmit+0x43b/0x660 drivers/net/loopback.c:90
__netdev_start_xmit include/linux/netdevice.h:5423 [inline]
netdev_start_xmit include/linux/netdevice.h:5432 [inline]
xmit_one net/core/dev.c:3918 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3934
sch_direct_xmit+0x257/0x4c0 net/sched/sch_generic.c:372
qdisc_restart net/sched/sch_generic.c:437 [inline]
__qdisc_run+0xb11/0x1620 net/sched/sch_generic.c:445
qdisc_run include/net/pkt_sched.h:120 [inline]
__dev_xmit_skb net/core/dev.c:4326 [inline]
__dev_queue_xmit+0x1c05/0x3820 net/core/dev.c:4865
dev_queue_xmit include/linux/netdevice.h:3455 [inline]
neigh_hh_output include/net/neighbour.h:544 [inline]
neigh_output include/net/neighbour.h:558 [inline]
ip_finish_output2+0xbda/0x10b0 net/ipv4/ip_output.c:236
NF_HOOK_COND include/linux/netfilter.h:314 [inline]
ip_output+0x29f/0x450 net/ipv4/ip_output.c:437
synproxy_send_client_synack+0x89b/0xde0 net/netfilter/nf_synproxy_core.c:487
nft_synproxy_eval_v4+0x362/0x4e0 net/netfilter/nft_synproxy.c:59
nft_synproxy_do_eval+0x335/0x550 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x48d/0x1b10 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:165 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:280 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:325
__netif_receive_skb_one_core net/core/dev.c:6241 [inline]
__netif_receive_skb net/core/dev.c:6354 [inline]
process_backlog+0xa34/0x1860 net/core/dev.c:6705
__napi_poll+0xaa/0x330 net/core/dev.c:7764
napi_poll net/core/dev.c:7827 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:7984
handle_softirqs+0x225/0x840 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:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x11f6/0x15f0 kernel/smp.c:912
Code: 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 8e 1a 0c 00 eb 37 f3 90 41 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 <74> 1e e8 73 1a 0c 00 eb e5 44 89 f1 80 e1 07 80 c1 03 38 c1 7c e3
RSP: 0018:ffffc9000626f700 EFLAGS: 00000202
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888053d5be00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000626f860 R08: ffffffff90575b37 R09: 1ffffffff20aeb66
R10: dffffc0000000000 R11: fffffbfff20aeb67 R12: 1ffff110170e8211
R13: ffff8880b863c648 R14: ffff8880b8741088 R15: 0000000000000001
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1077
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+0x5fd/0x1110 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:911
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 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