rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10501 ticks this GP) idle=7354/1/0x4000000000000000 softirq=217105/217105 fqs=0
rcu: 	(t=10502 jiffies g=182769 q=2633 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10502 jiffies! g182769 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=79520
rcu: rcu_preempt kthread starved for 10505 jiffies! g182769 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27040 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>
CPU: 1 UID: 0 PID: 30416 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:taprio_dequeue_from_txq+0xdc/0x980 net/sched/sch_taprio.c:720
Code: 74 08 4c 89 ff e8 e4 4e b6 f8 4c 89 74 24 08 49 8b 2f 4d 8d 7d 36 4c 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 ce 06 00 00 <48> 85 ed 0f 84 a9 06 00 00 49 89 ee 49 0f bf 2f 48 89 5c 24 28 4c
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88803b7f3000 RCX: dffffc0000000000
RDX: 0000000000000100 RSI: 0000000000000008 RDI: ffff88803b7f3000
RBP: ffff8880782ed000 R08: ffffffff89702086 R09: ffffffff8df41aa0
R10: 0000000000000001 R11: ffffffff89634ae0 R12: dffffc0000000000
R13: ffff888052a34000 R14: ffff888081a98800 R15: ffff888052a34036
FS:  000055558e9a1500(0000) GS:ffff888125f1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f45d7cc7d58 CR3: 00000000428fe000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 taprio_dequeue_tc_priority+0x1ac/0x750 net/sched/sch_taprio.c:793
 taprio_dequeue+0x186/0x550 net/sched/sch_taprio.c:-1
 dequeue_skb net/sched/sch_generic.c:297 [inline]
 qdisc_restart net/sched/sch_generic.c:402 [inline]
 __qdisc_run+0x23f/0x1510 net/sched/sch_generic.c:420
 qdisc_run+0xc7/0x300 include/net/pkt_sched.h:120
 net_tx_action+0x717/0x900 net/core/dev.c:5795
 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:userfaultfd_wp include/linux/userfaultfd_k.h:186 [inline]
RIP: 0010:__copy_present_ptes mm/memory.c:1099 [inline]
RIP: 0010:copy_present_ptes mm/memory.c:1181 [inline]
RIP: 0010:copy_pte_range mm/memory.c:1304 [inline]
RIP: 0010:copy_pmd_range+0x2330/0x7e00 mm/memory.c:1392
Code: ff ff ff fb 48 c7 c0 df ff ff ff 4c 0f 44 f8 31 ff e8 64 39 b2 ff 48 8b 8c 24 80 00 00 00 48 89 c8 48 c1 e8 03 42 80 3c 20 00 <74> 15 48 8b bc 24 80 00 00 00 e8 51 57 18 00 48 8b 8c 24 80 00 00
RSP: 0018:ffffc900041cf3e0 EFLAGS: 00000246
RAX: 1ffff1100b418c04 RBX: ffff88804be27160 RCX: ffff88805a0c6020
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900041cf670 R08: ffffea0001fecd47 R09: 1ffffd40003fd9a8
R10: dffffc0000000000 R11: fffff940003fd9a9 R12: dffffc0000000000
R13: ffff8880869fab70 R14: 840000007fb35805 R15: ffffffffffffffdf
 copy_pud_range mm/memory.c:1429 [inline]
 copy_p4d_range mm/memory.c:1453 [inline]
 copy_page_range+0xb88/0x11d0 mm/memory.c:1535
 dup_mmap+0xf4a/0x1b80 mm/mmap.c:1827
 dup_mm kernel/fork.c:1529 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1581
 copy_process+0x165d/0x3950 kernel/fork.c:2221
 kernel_clone+0x21e/0x820 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776
 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: 0033:0x7fdb34985e93
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffcfeca1048 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdb34985e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055558e9a17d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000fb2dd R15: 00007ffcfeca11e0
 </TASK>
sched: DL replenish lagged too much