rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5809/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=17933, q=1143337 ncpus=2)
task:syz-executor state:R running task stack:22848 pid:5809 tgid:5809 ppid:5808 task_flags:0x400100 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7188
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753
rcu_read_unlock include/linux/rcupdate.h:879 [inline]
class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0x1a66/0x23c0 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
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:1433 [inline]
__free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
__slab_free+0x263/0x2b0 mm/slub.c:5573
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:4538 [inline]
slab_alloc_node mm/slub.c:4866 [inline]
__kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5375
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
alloc_pipe_info+0xe8/0x4d0 fs/pipe.c:800
get_pipe_inode fs/pipe.c:896 [inline]
create_pipe_files+0x8a/0x7e0 fs/pipe.c:928
__do_pipe_flags+0x46/0x1f0 fs/pipe.c:990
do_pipe2+0xaa/0x190 fs/pipe.c:1038
__do_sys_pipe2 fs/pipe.c:1056 [inline]
__se_sys_pipe2 fs/pipe.c:1054 [inline]
__x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1054
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: 0033:0x7f90f9b9b849
RSP: 002b:00007ffddbe9cab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000125
RAX: ffffffffffffffda RBX: 0000555557afdf80 RCX: 00007f90f9b9b849
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 00007ffddbe9cac8
RBP: 00007ffddbe9d090 R08: 00007f90f9dece20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffddbe9ced0
R13: 0000555557b00808 R14: 0000555557b02a10 R15: 00007ffddbe9cc10
rcu: rcu_preempt kthread starved for 1827 jiffies! g17933 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:27648 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
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:436
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:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:__zone_watermark_unusable_free mm/page_alloc.c:3590 [inline]
RIP: 0010:zone_watermark_fast+0xed/0x230 mm/page_alloc.c:3704
Code: e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 ef e8 60 70 0e 00 48 8b 45 00 31 c9 48 85 c0 48 0f 4f c8 <49> 01 cd 4c 39 eb 4c 0f 4c eb 49 8d 46 38 48 63 2c 24 83 fd 05 0f
RSP: 0018:ffffc90000a079b8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00000000000009dc RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88813fffbb10
RBP: ffff88813fffbb10 R08: ffff88813fffbb17 R09: 1ffff11027fff762
R10: dffffc0000000000 R11: ffffed1027fff763 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88813fffb400 R15: 0000000000000801
FS: 0000000000000000(0000) GS:ffff888125554000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000067000 CR3: 000000007a538000 CR4: 00000000003526f0
Call Trace:
get_page_from_freelist+0x5d5/0x2580 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_slab_page mm/slub.c:3292 [inline]
allocate_slab+0x77/0x660 mm/slub.c:3481
new_slab mm/slub.c:3539 [inline]
refill_objects+0x331/0x3c0 mm/slub.c:7175
refill_sheaf mm/slub.c:2812 [inline]
__pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
alloc_from_pcs mm/slub.c:4717 [inline]
slab_alloc_node mm/slub.c:4851 [inline]
kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4873
dst_alloc+0x105/0x170 net/core/dst.c:90
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:53
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+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:6181 [inline]
__netif_receive_skb net/core/dev.c:6294 [inline]
process_backlog+0xaa3/0x1950 net/core/dev.c:6645
__napi_poll+0xae/0x340 net/core/dev.c:7709
napi_poll net/core/dev.c:7772 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7929
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:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 7e 6b 02 c3 cc cc cc cc cc cc cc 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 e3 92 19 00 fb f4 fc e9 02 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000242
RAX: 0000000000fafcfb RBX: ffffffff819a9c3a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8defbe6a RDI: ffffffff8c27d580
RBP: ffffc90000197f10 R08: ffff8880b873399b R09: 1ffff110170e6733
R10: dffffc0000000000 R11: ffffed10170e6734 R12: 0000000000000001
R13: 1ffff11003b59000 R14: 0000000000000001 R15: 1ffff11003b59000
arch_safe_halt arch/x86/kernel/process.c:766 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147