rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4966/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=29129, q=884 ncpus=2)
task:klogd state:R running task stack:25720 pid:4966 tgid:4966 ppid:1 task_flags:0x400100 flags:0x00080800
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__sanitizer_cov_trace_pc+0xb/0x70 kernel/kcov.c:213
Code: 64 00 be 03 00 00 00 5b e9 32 4f 13 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 85 6f 59 12 <48> 8b 34 24 65 48 8b 15 61 6f 59 12 a9 00 01 ff 00 74 1b f6 c4 01
RSP: 0018:ffffc9000492f6d0 EFLAGS: 00000286
RAX: 0000000080000000 RBX: 00000000000384cb RCX: ffffffff82865c1a
RDX: ffff88807f362540 RSI: ffffffff82865c24 RDI: ffff88807f362540
RBP: ffff88801ca80000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000003e40409 R14: 0000000000000000 R15: 0000000006bc03f9
page_ext_invalid mm/page_ext.c:249 [inline]
lookup_page_ext+0x8e/0x100 mm/page_ext.c:265
page_ext_iter_begin include/linux/page_ext.h:133 [inline]
__update_page_owner_free_handle.isra.0+0xa4/0x4d0 mm/page_owner.c:284
__reset_page_owner+0x93/0x190 mm/page_owner.c:321
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5362 [inline]
__kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5497
kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637
__alloc_skb+0x185/0x710 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
alloc_skb_with_frags+0xdd/0x760 net/core/skbuff.c:6769
sock_alloc_send_pskb+0x801/0x980 net/core/sock.c:3010
unix_dgram_sendmsg+0x3c7/0x1810 net/unix/af_unix.c:2136
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
__sys_sendto+0x48b/0x4e0 net/socket.c:2252
__do_sys_sendto net/socket.c:2259 [inline]
__se_sys_sendto net/socket.c:2255 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2255
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1b9d469407
RSP: 002b:00007fff4d8e4ce0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f1b9d319c80 RCX: 00007f1b9d469407
RDX: 000000000000005c RSI: 00007fff4d8e4e20 RDI: 0000000000000003
RBP: 00007fff4d8e5250 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fff4d8e5268
R13: 00007fff4d8e4e20 R14: 0000000000000041 R15: 00007fff4d8e4e20
rcu: rcu_preempt kthread starved for 7767 jiffies! g29129 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:27592 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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 0 to CPUs 1:
NMI backtrace for cpu 1
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 05/09/2026
RIP: 0010:in_softirq_really kernel/kcov.c:171 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data+0x24/0x90 kernel/kcov.c:246
Code: 90 90 90 90 90 90 65 8b 05 d9 76 59 12 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d b0 76 59 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 00 00 ff 00 74 05 c3 cc cc cc cc 8b 87 24 17 00 00 85 c0 74 f1
RSP: 0018:ffffc90000a08390 EFLAGS: 00000202
RAX: 0000000080000101 RBX: 0000000000000001 RCX: ffffffff8a1eae42
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88801ea82540
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff92000141077
R13: ffff8880584a4c00 R14: ffff8881f8b2f2d8 R15: ffff8881f8b2f2bc
FS: 0000000000000000(0000) GS:ffff888123eec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000007000 CR3: 000000003c86f000 CR4: 00000000003526f0
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
ip_output+0x3b2/0xc10 net/ipv4/ip_output.c:441
dst_output include/net/dst.h:470 [inline]
ip_local_out+0x193/0x1f0 net/ipv4/ip_output.c:131
synproxy_send_tcp.isra.0+0x481/0x680 net/netfilter/nf_synproxy_core.c:442
synproxy_send_client_synack+0x6ea/0x970 net/netfilter/nf_synproxy_core.c:487
nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:59 [inline]
nft_synproxy_do_eval+0xa1c/0xce0 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x2e5/0x19d0 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0xf3/0x400 net/netfilter/nft_chain_filter.c:162
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619
nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273
NF_HOOK include/linux/netfilter.h:316 [inline]
ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262
dst_input include/net/dst.h:480 [inline]
ip_rcv_finish net/ipv4/ip_input.c:492 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:612
__netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6206
__netif_receive_skb+0x1f/0x120 net/core/dev.c:6319
process_backlog+0x37a/0x1580 net/core/dev.c:6670
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7729
napi_poll net/core/dev.c:7792 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:7949
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 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+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 06 8e 02 c3 cc cc cc cc 0f 1f 00 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 c3 d9 12 00 fb f4 bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197e00 EFLAGS: 00000246
RAX: 0000000002d40f4b RBX: ffff88801ea82540 RCX: ffffffff8bb8c2d5
RDX: 0000000000000000 RSI: ffffffff8e1a29fc RDI: ffffffff8c400c80
RBP: ffffed1003d504a8 R08: 0000000000000001 R09: ffffed10170a678d
R10: ffff8880b8533c6b R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:768
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x158