rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4328/1:b..l
(detected by 0, t=10502 jiffies, g=8229, q=377)
task:syz.1.13 state:R running task stack:23760 pid: 4328 ppid: 4189 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__local_bh_enable_ip+0x147/0x1c0 kernel/softirq.c:408
rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
ip_finish_output2+0xd6e/0x10e0 net/ipv4/ip_output.c:229
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0x2ba/0x3e0 net/ipv4/ip_output.c:434
dst_output include/net/dst.h:452 [inline]
ip_local_out net/ipv4/ip_output.c:126 [inline]
ip_send_skb+0x129/0x1c0 net/ipv4/ip_output.c:1590
udp_send_skb+0x93f/0x1330 net/ipv4/udp.c:991
udp_sendmsg+0x1ac7/0x2350 net/ipv4/udp.c:1279
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
__sys_sendmmsg+0x2ba/0x500 net/socket.c:2586
__do_sys_sendmmsg net/socket.c:2615 [inline]
__se_sys_sendmmsg net/socket.c:2612 [inline]
__x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2612
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f699373ce59
RSP: 002b:00007f6991975028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f69939b6090 RCX: 00007f699373ce59
RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000004
RBP: 00007f69937d2e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f69939b6128 R14: 00007f69939b6090 R15: 00007ffee4c86de8
rcu: rcu_preempt kthread starved for 10529 jiffies! g8229 f0x0 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:27024 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:__free_object+0x96e/0xa60 arch/x86/include/asm/irqflags.h:-1
Code: 00 00 00 00 9c 8f 84 24 a0 00 00 00 f7 84 24 a0 00 00 00 00 02 00 00 42 c6 44 28 08 f8 75 7b f7 44 24 20 00 02 00 00 74 01 fb <48> 8b 44 24 30 48 b9 f8 f8 f8 f8 f8 f8 f8 f8 4a 89 4c 28 10 4a 89
RSP: 0018:ffffc90000d47980 EFLAGS: 00000206
RAX: 1ffff920001a8f3c RBX: ffff88814c4f05f0 RCX: c3f8713b30a38600
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a79c980
RBP: ffffc90000d47b58 R08: ffffc90000d47adf R09: ffffc90000d47a60
R10: dffffc0000000000 R11: fffff520001a8f5c R12: ffff8880b9037018
R13: dffffc0000000000 R14: ffff8880b9037010 R15: ffff88814c4f05e8
free_object lib/debugobjects.c:427 [inline]
debug_object_free+0x2c6/0x470 lib/debugobjects.c:852
destroy_timer_on_stack kernel/time/timer.c:759 [inline]
schedule_timeout+0x19d/0x2d0 kernel/time/timer.c:2121
rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:2021
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730
Code: b7 48 89 df e8 a6 ed fa f7 eb ad e8 df b0 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d f7 a8 62 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c007dc8 EFLAGS: 000002c6
RAX: 76180344e7869200 RBX: ffffffff8c0bc480 RCX: 76180344e7869200
RDX: 0000000000000001 RSI: ffffffff8a2b2be0 RDI: ffffffff8a79c980
RBP: ffffffff8c007ef8 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 1ffffffff1800fc4
R13: dffffc0000000000 R14: 1ffffffff1817890 R15: 0000000000000000
default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
cpuidle_idle_call kernel/sched/idle.c:202 [inline]
do_idle+0x251/0x650 kernel/sched/idle.c:326
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:424
start_kernel+0x489/0x540 init/main.c:1153
secondary_startup_64_no_verify+0xb1/0xbb