rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=dc1c/1/0x4000000000000004 softirq=56047/56047 fqs=95
rcu: 	(t=10500 jiffies g=43889 q=3067 ncpus=2)
rcu: rcu_preempt kthread starved for 10278 jiffies! g43889 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:27392 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 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+0x599/0xb30 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: 12573 Comm: syz.2.1676 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:217
Code: 08 f0 76 92 65 8b 15 b8 a5 b5 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 32 48 8d 7e 01 8b 89 4c
RSP: 0018:ffffc9000bbf7318 EFLAGS: 00000246
RAX: ffffffff81b5ba87 RBX: 1ffff11017128101 RCX: ffff88802e699e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000bbf74a0 R08: ffffffff8f805a77 R09: 1ffffffff1f00b4e
R10: dffffc0000000000 R11: fffffbfff1f00b4f R12: ffff8880b8940808
R13: dffffc0000000000 R14: ffff8880b883b9c0 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881260b1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200001000000 CR3: 000000000dd3a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xce7/0x12b0 kernel/smp.c:877
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x6b1/0x1280 arch/x86/mm/tlb.c:1472
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
 tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 free_ldt_pgtables+0x17b/0x320 arch/x86/kernel/ldt.c:411
 arch_exit_mmap arch/x86/include/asm/mmu_context.h:234 [inline]
 exit_mmap+0x174/0xb20 mm/mmap.c:1266
 __mmput+0x118/0x430 kernel/fork.c:1130
 exit_mm+0x1da/0x2c0 kernel/exit.c:583
 do_exit+0x658/0x2310 kernel/exit.c:961
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1114
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3024b8f749
Code: Unable to access opcode bytes at 0x7f3024b8f71f.
RSP: 002b:00007f3025a45038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: 000000000003ff6f RBX: 00007f3024de6090 RCX: 00007f3024b8f749
RDX: 03ffffffffffff67 RSI: 0000200000002440 RDI: 0000000000000005
RBP: 00007f3024c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3024de6128 R14: 00007f3024de6090 R15: 00007fff14b447e8
 </TASK>
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
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 f0 76 92 65 8b 15 b8 a5 b5 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:ffffc90000a08ad0 EFLAGS: 00000246
RAX: ffffffff896202fa RBX: ffff8880545df000 RCX: ffff88801ce9db80
RDX: 0000000000000100 RSI: 0000000000000009 RDI: ffff8880545df000
RBP: 1ffff1100a8bbe6a R08: ffffffff89615756 R09: ffffffff8df41cc0
R10: 0000000000000001 R11: ffffffff89549fc0 R12: dffffc0000000000
R13: ffff8880545df354 R14: ffff888054c18c00 R15: 0000000000000009
FS:  0000000000000000(0000) GS:ffff8881261b1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c28854e CR3: 0000000069074000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 taprio_dequeue_from_txq+0x2a/0x980 net/sched/sch_taprio.c:709
 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+0x7ac/0x9f0 net/core/dev.c:5781
 handle_softirqs+0x27d/0x850 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 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:do_idle+0x15f/0x520 kernel/sched/idle.c:334
Code: 17 e9 0d 0f 83 c4 03 00 00 e8 bd c4 d1 ff 83 3d e6 17 e9 0d 00 75 09 e8 af 0e b2 09 85 c0 74 32 e8 96 aa 1b 00 e8 91 29 b2 09 <e8> 4c f7 ff ff 48 b8 00 00 00 00 00 fc ff df 41 80 7c 05 00 00 0f
RSP: 0018:ffffc90000197e00 EFLAGS: 00000286
RAX: 5ec28cdef737a400 RBX: ffff88801ce9db80 RCX: 5ec28cdef737a400
RDX: 0000000000000000 RSI: ffffffff8d76bd39 RDI: ffffffff8bbfc660
RBP: ffffc90000197f10 R08: ffffffff8f805a77 R09: 1ffffffff1f00b4e
R10: dffffc0000000000 R11: fffffbfff1f00b4f R12: ffffffff8f805a70
R13: 1ffff110039d3b70 R14: 0000000000000001 R15: 0000000000000001
 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>
sched: DL replenish lagged too much