rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20189/1:b..l P20420/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=140545, q=119 ncpus=2)
task:syz-executor state:R running task stack:21736 pid:20420 ppid:20402 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
copy_pte_range mm/memory.c:1107 [inline]
copy_pmd_range mm/memory.c:1168 [inline]
copy_pud_range mm/memory.c:1205 [inline]
copy_p4d_range mm/memory.c:1229 [inline]
copy_page_range+0x2ba0/0x3670 mm/memory.c:1323
dup_mmap kernel/fork.c:768 [inline]
dup_mm kernel/fork.c:1693 [inline]
copy_mm+0x1281/0x1d80 kernel/fork.c:1742
copy_process+0x16f7/0x3d80 kernel/fork.c:2507
kernel_clone+0x24b/0x8a0 kernel/fork.c:2915
__do_sys_clone kernel/fork.c:3058 [inline]
__se_sys_clone kernel/fork.c:3042 [inline]
__x64_sys_clone+0x1b7/0x230 kernel/fork.c:3042
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f45a15c5292
RSP: 002b:00007ffcc996e140 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffcc996e140 RCX: 00007f45a15c5292
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffcc996e2cc R08: 0000000000000000 R09: 0000000000000001
R10: 00005555926977d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000001588d5 R15: 00007ffcc996e320
task:syz-executor state:R running task stack:24232 pid:20189 ppid:5756 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
zap_pte_range mm/memory.c:1523 [inline]
zap_pmd_range mm/memory.c:1571 [inline]
zap_pud_range mm/memory.c:1600 [inline]
zap_p4d_range mm/memory.c:1621 [inline]
unmap_page_range+0x2315/0x3000 mm/memory.c:1642
unmap_vmas+0x286/0x3f0 mm/memory.c:1732
exit_mmap+0x238/0xb90 mm/mmap.c:3302
__mmput+0x118/0x3c0 kernel/fork.c:1356
exit_mm+0x1f2/0x2c0 kernel/exit.c:569
do_exit+0x8dd/0x2460 kernel/exit.c:870
do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
get_signal+0x12fc/0x13f0 kernel/signal.c:2902
arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff4de957997
RSP: 002b:00007ffe40e47f10 EFLAGS: 00000202 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 000055555ee39500 RCX: 00007ff4de957997
RDX: 0000000040000000 RSI: 00007ffe40e47f6c RDI: ffffffffffffffff
RBP: 00007ffe40e47f6c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffe40e481c8 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10163 jiffies! g140545 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:27656 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:unwind_next_frame+0x717/0x2970 arch/x86/kernel/unwind_orc.c:512
Code: 00 00 48 89 5c 24 30 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 51 1c 00 00 41 0f b7 1f c1 eb 0b 80 e3 01 48 8b 44 24 38 <42> 0f b6 04 28 84 c0 0f 85 55 1c 00 00 48 8b 44 24 08 88 18 45 0f
RSP: 0018:ffffc900001efcf8 EFLAGS: 00000246
RAX: 1ffff9200003dfbf RBX: 0000000000000000 RCX: ffff88801c263c00
RDX: 0000000000000100 RSI: ffffffff8cfa07c0 RDI: 0000000000000002
RBP: ffffc900001efe18 R08: ffff88801c263c00 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000100 R12: ffffc900001efdc8
R13: dffffc0000000000 R14: ffffffff8f100b91 R15: ffffffff8f100b90
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f45a23456b8 CR3: 0000000076d14000 CR4: 00000000003506e0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
kmem_cache_free+0xf8/0x270 mm/slub.c:3852
skb_kfree_head net/core/skbuff.c:947 [inline]
skb_free_head net/core/skbuff.c:961 [inline]
skb_release_data+0x60a/0x800 net/core/skbuff.c:991
skb_release_all net/core/skbuff.c:1057 [inline]
__kfree_skb net/core/skbuff.c:1071 [inline]
consume_skb+0xb2/0x110 net/core/skbuff.c:1287
nft_synproxy_eval_v6+0x353/0x4e0 net/netfilter/nft_synproxy.c:91
nft_synproxy_do_eval+0x3cb/0x570 net/netfilter/nft_synproxy.c:145
expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
nft_do_chain+0x44e/0x1600 net/netfilter/nf_tables_core.c:288
nft_do_chain_inet+0x29b/0x380 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:259 [inline]
NF_HOOK+0x21d/0x3b0 include/linux/netfilter.h:302
NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
__netif_receive_skb_one_core net/core/dev.c:5646 [inline]
__netif_receive_skb+0xcc/0x290 net/core/dev.c:5760
process_backlog+0x391/0x6f0 net/core/dev.c:6088
__napi_poll+0xc0/0x460 net/core/dev.c:6650
napi_poll net/core/dev.c:6717 [inline]
net_rx_action+0x616/0xc40 net/core/dev.c:6853
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 39 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d e3 f3 41 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6
RAX: b492e132313c8c00 RBX: ffffffff8162a8f1 RCX: b492e132313c8c00
RDX: 0000000000000001 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: 1ffff92000030fc8
R13: dffffc0000000000 R14: 1ffff1100384c780 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:178 [inline]
do_idle+0x221/0x590 kernel/sched/idle.c:302
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401
start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
secondary_startup_64_no_verify+0x179/0x17b