rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (1 GPs behind) idle=eaf4/1/0x4000000000000000 softirq=25074/25076 fqs=776
(t=10502 jiffies g=28105 q=368 ncpus=2)
rcu: rcu_preempt kthread starved for 8940 jiffies! g28105 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:27456 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741
CPU: 0 PID: 8567 Comm: syz.1.1027 Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:cake_heap_get_backlog net/sched/sch_cake.c:1472 [inline]
RIP: 0010:cake_heapify+0x181/0x6a0 net/sched/sch_cake.c:1486
Code: fc ff df 89 d8 c1 e8 03 25 ff 03 00 00 83 e3 07 48 69 cb d0 98 01 00 49 03 0c 24 4c 8d bc 81 00 40 01 00 4c 89 f8 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 e9 03 00 00 45 8b 27 44 89 e7 8b 5c 24 0c
RSP: 0018:ffffc90000006f60 EFLAGS: 00000a02
RAX: 1ffff1100a3927c2 RBX: 0000000000000005 RCX: ffff888051c7fc10
RDX: dffffc0000000000 RSI: 0000000000000202 RDI: 0000000000001000
RBP: 0000000000000202 R08: dffffc0000000000 R09: fffffbfff215ba81
R10: fffffbfff215ba81 R11: 1ffffffff215ba80 R12: ffff8880577902d0
R13: 0000000000000405 R14: 0000000000000202 R15: ffff888051c93e10
FS: 00007fc0a29ff6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0a29fef98 CR3: 000000007c45a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
cake_drop net/sched/sch_cake.c:1575 [inline]
cake_enqueue+0x305a/0x7ee0 net/sched/sch_cake.c:1945
qdisc_enqueue include/net/sch_generic.h:816 [inline]
netem_dequeue+0xcfc/0x13c0 net/sched/sch_netem.c:737
dequeue_skb net/sched/sch_generic.c:292 [inline]
qdisc_restart net/sched/sch_generic.c:397 [inline]
__qdisc_run+0x247/0x15f0 net/sched/sch_generic.c:415
__dev_xmit_skb net/core/dev.c:3958 [inline]
__dev_queue_xmit+0x107e/0x3760 net/core/dev.c:4300
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
tipc_l2_send_msg+0x30f/0x3d0 net/tipc/bearer.c:518
tipc_bearer_xmit_skb+0x2a9/0x3f0 net/tipc/bearer.c:577
tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
expire_timers kernel/time/timer.c:1549 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1820
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 2e e9 66 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 b6 74 37 f7 65 8b 05 87 35 e2 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9001c36f5a0 EFLAGS: 00000206
RAX: 3304239e3b33e200 RBX: 0000000000000a06 RCX: 3304239e3b33e200
RDX: dffffc0000000000 RSI: ffffffff8a8c0460 RDI: 0000000000000001
RBP: ffffc9001c36f630 R08: dffffc0000000000 R09: fffffbfff215ba5d
R10: fffffbfff215ba5d R11: 1ffffffff215ba5c R12: dffffc0000000000
R13: 0000000000000000 R14: ffff88807be106c0 R15: 1ffff9200386deb4
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock kernel/sched/wait.c:140 [inline]
__wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:208
__unix_dgram_recvmsg+0x498/0xd70 net/unix/af_unix.c:2478
____sys_recvmsg+0x292/0x580 net/socket.c:-1
___sys_recvmsg+0x1b2/0x510 net/socket.c:2780
do_recvmmsg+0x359/0x7d0 net/socket.c:2874
__sys_recvmmsg net/socket.c:2953 [inline]
__do_sys_recvmmsg net/socket.c:2976 [inline]
__se_sys_recvmmsg net/socket.c:2969 [inline]
__x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2969
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc0a2b8eb69
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc0a29ff038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fc0a2db6160 RCX: 00007fc0a2b8eb69
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007fc0a2c11df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fc0a2db6160 R15: 00007fff2b085238