rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=55c4/1/0x4000000000000000 softirq=249633/249636 fqs=47
rcu: 	(t=10502 jiffies g=260821 q=66 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10408 jiffies! g260821 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=158059
rcu: rcu_preempt kthread starved for 10411 jiffies! g260821 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27808 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 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+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 13 e3 02 00 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 73 c1 0e 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000007568 EFLAGS: 00000246
RAX: ffffffff81733311 RBX: 0000000000000003 RCX: ffffffff8dc95340
RDX: 0000000000000100 RSI: ffffffff8d79207b RDI: ffffffff8bc083e0
RBP: 0000000000000003 R08: ffffffff8f822277 R09: 1ffffffff1f0444e
R10: dffffc0000000000 R11: fffffbfff1f0444f R12: 0000000000000200
R13: 0000000000000000 R14: ffff888031ad0158 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9302612368 CR3: 000000007c156000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 kvm_wait+0x166/0x1c0 arch/x86/kernel/kvm.c:1085
 pv_wait arch/x86/include/asm/paravirt.h:569 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline]
 __pv_queued_spin_lock_slowpath+0x7bf/0xb60 kernel/locking/qspinlock.c:325
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
 queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116
 spin_lock include/linux/spinlock.h:351 [inline]
 __dev_xmit_skb net/core/dev.c:4207 [inline]
 __dev_queue_xmit+0xb82/0x31c0 net/core/dev.c:4785
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 tipc_l2_send_msg+0x337/0x400 net/tipc/bearer.c:516
 tipc_bearer_xmit_skb+0x2b3/0x400 net/tipc/bearer.c:575
 tipc_disc_timeout+0x580/0x6d0 net/tipc/discover.c:338
 call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 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: 13 e3 02 00 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 73 c1 0e 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07dc0 EFLAGS: 000002c2
RAX: 0000000005abab0b RBX: ffffffff819713ee RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d79207b RDI: ffffffff8bc083e0
RBP: ffffffff8dc07eb0 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f822270
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
 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:191 [inline]
 do_idle+0x1be/0x4d0 kernel/sched/idle.c:332
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
 rest_init+0x2de/0x300 init/main.c:757
 start_kernel+0x381/0x3d0 init/main.c:1206
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>
CPU: 1 UID: 0 PID: 3925 Comm: syz.3.6738 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2f/0x70 kernel/kcov.c:217
Code: 8b 04 24 65 48 8b 0c 25 08 10 80 92 65 8b 15 58 18 bf 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 6c 16 00 00 00 <74> 2c 8b 91 48 16 00 00 83 fa 02 75 21 48 8b 91 50 16 00 00 48 8b
RSP: 0018:ffffc90000a08688 EFLAGS: 00000246
RAX: ffffffff895b30fc RBX: 0000000000000001 RCX: ffff88805d5f1e80
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000004
R10: 0000000000000008 R11: 0000000000000100 R12: ffff88803b5b81dc
R13: ffff888043752c00 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f64e88ef6c0(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000158030 CR3: 00000000338c0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __tcf_classify net/sched/cls_api.c:1728 [inline]
 tcf_classify+0x58c/0x1140 net/sched/cls_api.c:1860
 hfsc_classify net/sched/sch_hfsc.c:1146 [inline]
 hfsc_enqueue+0x323/0xf20 net/sched/sch_hfsc.c:1545
 dev_qdisc_enqueue+0x4e/0x240 net/core/dev.c:4134
 __dev_xmit_skb net/core/dev.c:4249 [inline]
 __dev_queue_xmit+0x18d8/0x31c0 net/core/dev.c:4785
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 neigh_hh_output include/net/neighbour.h:540 [inline]
 neigh_output include/net/neighbour.h:554 [inline]
 ip_finish_output2+0xb52/0x1000 net/ipv4/ip_output.c:237
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
 igmpv3_send_cr net/ipv4/igmp.c:726 [inline]
 igmp_ifc_timer_expire+0xbb6/0xde0 net/ipv4/igmp.c:816
 call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216
Code: 8b 3d 54 fe d9 0b 48 89 de 5b e9 b3 fb 5a 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 10 80 92 65 8b 15 58 18 bf 10 81 e2 00 01 ff 00
RSP: 0018:ffffc9001cd9fa38 EFLAGS: 00000246
RAX: ffffffff892d1d96 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9001cd9fce8 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9001cd9fc30 R08: ffffc9001cd9fad7 R09: 1ffff920039b3f5a
R10: dffffc0000000000 R11: fffff520039b3f5b R12: ffffc9001cd9fce0
R13: dffffc0000000000 R14: 0000000000000002 R15: 1ffff920039b3f50
 __copy_msghdr net/socket.c:2493 [inline]
 copy_msghdr_from_user net/socket.c:2525 [inline]
 recvmsg_copy_msghdr net/socket.c:2778 [inline]
 ___sys_recvmsg+0x396/0x510 net/socket.c:2850
 do_recvmmsg+0x307/0x770 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3039
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f64e798f749
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:00007f64e88ef038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f64e7be6090 RCX: 00007f64e798f749
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f64e7a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f64e7be6128 R14: 00007f64e7be6090 R15: 00007f64e7d0fa28
 </TASK>
sched: DL replenish lagged too much