rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=314c/1/0x4000000000000000 softirq=144859/144861 fqs=232
rcu: 	(t=10500 jiffies g=145573 q=210 ncpus=2)
rcu: rcu_preempt kthread starved for 10030 jiffies! g145573 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:27648 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6867
 __schedule_loop kernel/sched/core.c:6949 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6964
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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: cc cc cc cc 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 53 01 0e 00 f3 0f 1e fa fb f4 <e9> 08 e3 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 000002c6
RAX: 0000000000e52a11 RBX: ffffffff8197287e RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d79361f RDI: ffffffff8bc084e0
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f822e70
R13: 1ffff11003959b70 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125f1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe71f606c17 CR3: 00000000347bc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 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
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>
CPU: 0 UID: 0 PID: 17867 Comm: syz-executor 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:tcf_classify+0x3c/0x1140 net/sched/cls_api.c:1816
Code: 44 89 44 24 4c 49 89 cc 48 89 d3 48 89 74 24 30 49 89 fd 49 be 00 00 00 00 00 fc ff df e8 bc 47 65 f8 48 85 db 48 89 5c 24 20 <0f> 84 8e 00 00 00 e8 a9 47 65 f8 4c 8d 7b 30 4c 89 f8 48 c1 e8 03
RSP: 0018:ffffc90000007690 EFLAGS: 00000286
RAX: ffffffff895bc5c4 RBX: ffff888048ad1100 RCX: ffff8880316f9e80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff888073a77c80
RBP: ffffc90000007810 R08: 0000000000000000 R09: 0000000000000004
R10: 0000000000000008 R11: 0000000000000100 R12: ffffc900000077a0
R13: ffff888073a77c80 R14: dffffc0000000000 R15: ffff888048ad1100
FS:  0000555592aca500(0000) GS:ffff888125e1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001340 CR3: 0000000078dfa000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 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:4147
 __dev_xmit_skb net/core/dev.c:4262 [inline]
 __dev_queue_xmit+0x1873/0x3100 net/core/dev.c:4798
 neigh_output include/net/neighbour.h:556 [inline]
 ip_finish_output2+0xbb6/0x1000 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:finish_task_switch+0x242/0x940 kernel/sched/core.c:5118
Code: 0f 84 c2 01 00 00 48 85 db 0f 85 e9 01 00 00 e9 6b 05 00 00 4c 8b 75 d0 4c 89 e7 e8 f8 32 cb 09 e8 33 22 37 00 fb 4c 8b 65 c0 <49> 8d bc 24 48 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90004427958 EFLAGS: 00000202
RAX: 0000000000077657 RBX: 0000000000000000 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8d79361f RDI: ffffffff8bc084e0
RBP: ffffc900044279b0 R08: ffffffff8f822e77 R09: 1ffffffff1f045ce
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: ffff8880316f9e80
R13: dffffc0000000000 R14: ffff88802e229e80 R15: ffff8880b863b498
 context_switch kernel/sched/core.c:5263 [inline]
 __schedule+0x14a3/0x4fd0 kernel/sched/core.c:6867
 __schedule_loop kernel/sched/core.c:6949 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6964
 do_nanosleep+0x1c5/0x610 kernel/time/hrtimer.c:2116
 hrtimer_nanosleep+0x169/0x360 kernel/time/hrtimer.c:2163
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1398 [inline]
 __se_sys_clock_nanosleep+0x339/0x390 kernel/time/posix-timers.c:1375
 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: 0033:0x7fbe4efc2005
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8
RSP: 002b:00007fbe4f30fd40 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 00000000000000b9 RCX: 00007fbe4efc2005
RDX: 00007fbe4f30fd80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fbe4f30fdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 00000000000f214d R15: 00007fbe4f30fe40
 </TASK>
sched: DL replenish lagged too much