rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14008/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=85937, q=337 ncpus=2)
task:syz.3.2128 state:R running task stack:26632 pid:14008 tgid:14007 ppid:5842 task_flags:0x40044c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__read_once_word_nocheck+0x0/0x10 include/asm-generic/rwonce.h:67
Code: e8 45 fd b1 00 48 ba 00 00 00 00 00 fc ff df e9 88 fc ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <48> 8b 07 e9 58 28 d5 09 cc cc cc cc cc cc cc cc 90 90 90 90 90 90
RSP: 0018:ffffc9000caa6f70 EFLAGS: 00000202
RAX: ffffc9000caa7f01 RBX: ffffc9000caa7f40 RCX: 1ffff92001954e01
RDX: ffffffff90b03cca RSI: 0000000000000002 RDI: ffffc9000caa7f40
RBP: 1ffff92001954e0a R08: 0000000000000001 R09: ffffffff81738d25
R10: ffffc9000caa7098 R11: ffffffff81ac2cb0 R12: ffffc9000caa8000
R13: 1ffff92001954e0b R14: ffffc9000caa7048 R15: ffffc9000caa0000
deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline]
unwind_next_frame+0xc3c/0x2390 arch/x86/kernel/unwind_orc.c:585
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963
folios_put_refs+0x584/0x670 mm/swap.c:1002
free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355
__tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
exit_mmap+0x444/0xb40 mm/mmap.c:1293
__mmput+0x118/0x430 kernel/fork.c:1133
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:954
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6ea38efc9
RSP: 002b:00007fc6eb2bd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fc6ea5e5fa8 RCX: 00007fc6ea38efc9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc6ea5e5fa8
RBP: 00007fc6ea5e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6ea5e6038 R14: 00007fc6ea70f940 R15: 00007fc6ea70fa28
rcu: rcu_preempt kthread starved for 10360 jiffies! g85937 f0x0 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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 10/02/2025
RIP: 0010:stack_depot_save_flags+0x55/0x860 lib/stackdepot.c:661
Code: 0f 83 48 01 00 00 41 89 d5 49 89 fe 89 4c 24 04 e8 20 d7 ea fc 41 89 c2 31 c0 45 85 d2 0f 84 f1 03 00 00 80 3d db 67 ec 14 00 <0f> 85 e4 03 00 00 43 8d 34 12 42 8d 2c d5 7b 71 f5 75 83 fe 04 72
RSP: 0018:ffffc90000a07cf8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000082801 RCX: 0000000000000001
RDX: 0000000000082801 RSI: 000000000000001e RDI: ffffc90000a07d60
RBP: ffffc90000a07f88 R08: 0000000000000003 R09: ffffffff81738d25
R10: 0000000000000017 R11: ffffffff81ac2cb0 R12: 0000000000000101
R13: 0000000000082820 R14: ffffc90000a07d60 R15: ffffc90000a07d60
FS: 0000000000000000(0000) GS:ffff88812623e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf86f1102b CR3: 000000005fcac000 CR4: 00000000003526f0
Call Trace:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x4f/0x80 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:342 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4962 [inline]
slab_alloc_node mm/slub.c:5272 [inline]
kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5324
kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:579
__alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1383 [inline]
synproxy_send_client_synack_ipv6+0x169/0xca0 net/netfilter/nf_synproxy_core.c:873
nft_synproxy_eval_v6+0x36e/0x560 net/netfilter/nft_synproxy.c:90
nft_synproxy_do_eval+0x3d7/0x570 net/netfilter/nft_synproxy.c:145
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 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+0x206/0x3a0 include/linux/netfilter.h:316
ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6079 [inline]
__netif_receive_skb+0xd3/0x380 net/core/dev.c:6192
process_backlog+0x60e/0x14f0 net/core/dev.c:6544
__napi_poll+0xc7/0x360 net/core/dev.c:7594
napi_poll net/core/dev.c:7657 [inline]
net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784
handle_softirqs+0x286/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 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 33 31 22 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: 79251b864047cc00 RBX: ffffffff81967b87 RCX: 79251b864047cc00
RDX: 0000000000000001 RSI: ffffffff8d70bc84 RDI: ffffffff8bbf0460
RBP: ffffc90000197f10 R08: ffff8880b8932fdb R09: 1ffff110171265fb
R10: dffffc0000000000 R11: ffffed10171265fc R12: ffffffff8f7cd370
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11003952b58
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e7/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x147