rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1837/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=224357, q=805732 ncpus=2)
task:syz.5.6571 state:R running task stack:24960 pid:1837 tgid:1837 ppid:27495 task_flags:0x40004c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2d7/0x3d0 kernel/locking/lockdep.c:5893
Code: 37 7a 11 00 00 00 00 eb b5 e8 25 64 0b 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 a5 f1 79 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 8a 4a 0e 0a cc 48 8d 3d d2 1a 73
RSP: 0018:ffffc9000d03f2c0 EFLAGS: 00000286
RAX: 5f0f744a48b30300 RBX: 0000000000000202 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e161e0a RDI: ffffffff8c27a480
RBP: ffff8880525ec7c0 R08: ffffc9000d03f8f0 R09: 0000000000000000
R10: ffffc9000d03f418 R11: fffff52001a07e85 R12: 0000000000000001
R13: 0000000000000001 R14: ffffffff8e7602e0 R15: ffff8880525ebc80
rcu_lock_release include/linux/rcupdate.h:322 [inline]
rcu_read_unlock include/linux/rcupdate.h:881 [inline]
class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3131 [inline]
call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
slab_free_hook mm/slub.c:2651 [inline]
slab_free mm/slub.c:6124 [inline]
kmem_cache_free+0x439/0x630 mm/slub.c:6254
anon_vma_free mm/rmap.c:137 [inline]
__put_anon_vma+0x12b/0x2d0 mm/rmap.c:2889
put_anon_vma mm/internal.h:215 [inline]
unlink_anon_vmas+0x58b/0x730 mm/rmap.c:529
free_pgtables+0x663/0xb70 mm/memory.c:414
exit_mmap+0x490/0xa10 mm/mmap.c:1314
__mmput+0x118/0x430 kernel/fork.c:1174
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x62e/0x2320 kernel/exit.c:959
do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
__do_sys_exit_group kernel/exit.c:1123 [inline]
__se_sys_exit_group kernel/exit.c:1121 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b0919c629
RSP: 002b:00007f2b0953fd88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2b0919c629
RDX: 0000555567b91808 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f2b0953fdec R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000000a6
R13: 00000000000927c0 R14: 0000000000166bd1 R15: 00007f2b0953fe40
rcu: rcu_preempt kthread starved for 4094 jiffies! g224357 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:27776 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
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+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 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: 21837 Comm: kworker/u8:25 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:unwind_next_frame+0x138f/0x23c0 arch/x86/kernel/unwind_orc.c:656
Code: 14 24 4d 89 3c 24 41 0f b6 44 2d 00 84 c0 0f 85 02 0e 00 00 c6 03 00 4c 8b 64 24 48 4c 8b 7c 24 28 48 8b 44 24 40 0f b6 04 28 <84> c0 0f 85 6c 0b 00 00 41 0f b6 04 2f 84 c0 0f 85 83 0b 00 00 0f
RSP: 0018:ffffc90000006d98 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90000006ea0 RCX: 0000000000000000
RDX: ffffffff90a495f0 RSI: 0000000000000000 RDI: ffffc90000006ec8
RBP: dffffc0000000000 R08: ffffc90000006ec7 R09: 0000000000000000
R10: ffffc90000006eb8 R11: fffff52000000dd9 R12: ffffc90000006eb8
R13: 1ffff92000000dcf R14: ffffc90000006e68 R15: 1ffffffff21492be
FS: 0000000000000000(0000) GS:ffff888125466000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b884863db CR3: 000000000e54c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 3a810b1eb6134bdc DR6: 00000000ffff0ff0 DR7: 0000000000000400
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
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4501 [inline]
slab_alloc_node mm/slub.c:4830 [inline]
kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4882
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
synproxy_send_client_synack+0x172/0xe30 net/netfilter/nf_synproxy_core.c:461
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+0x45e/0x1990 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x29d/0x380 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+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:6156 [inline]
__netif_receive_skb net/core/dev.c:6269 [inline]
process_backlog+0xaa3/0x1950 net/core/dev.c:6621
__napi_poll+0xae/0x340 net/core/dev.c:7685
napi_poll net/core/dev.c:7748 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7900
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
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+0xcea/0x12c0 kernel/smp.c:877
Code: 89 ee 83 e6 01 31 ff e8 24 e3 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 cf de 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 b3 de 0b 00 eb e4 44
RSP: 0018:ffffc9000495f720 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110170e812d RCX: ffff8880282ddac0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000495f860 R08: ffffffff901172b7 R09: 1ffffffff2022e56
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: ffff8880b8740968
R13: dffffc0000000000 R14: ffff8880b863bf80 R15: 0000000000000001
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
on_each_cpu include/linux/smp.h:72 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2746 [inline]
smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2956
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:899
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245