rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=0d1c/1/0x4000000000000000 softirq=13314/13314 fqs=0
rcu: 	(t=10500 jiffies g=12777 q=22 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g12777 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=4137
rcu: rcu_preempt kthread starved for 10500 jiffies! g12777 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:26568 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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 PID: 11 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
RIP: 0010:validate_chain kernel/locking/lockdep.c:3836 [inline]
RIP: 0010:__lock_acquire+0x12f1/0x7c80 kernel/locking/lockdep.c:5137
Code: 48 89 df e8 91 ed 75 00 49 b8 00 00 00 00 00 fc ff df 48 83 3b 00 0f 84 a6 4b 00 00 49 c1 e4 20 48 8b 44 24 48 42 0f b6 04 00 <84> c0 0f 85 97 59 00 00 4d 09 f4 41 8b 07 89 c1 81 e1 00 80 04 00
RSP: 0018:ffffc900001f0860 EFLAGS: 00000006
RAX: 0000000000000000 RBX: ffffffff906fc4d0 RCX: ffffffff816710b0
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90d94500
RBP: ffffc900001f0aa8 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: 2f566e4e00000000
R13: ffff888019e7bc00 R14: 0000000045871fd7 R15: ffff888019e7c7f0
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003c80 CR3: 0000000076cbd000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
 debug_object_activate+0x6c/0x4b0 lib/debugobjects.c:709
 debug_hrtimer_activate kernel/time/hrtimer.c:450 [inline]
 debug_activate kernel/time/hrtimer.c:505 [inline]
 enqueue_hrtimer+0x30/0x370 kernel/time/hrtimer.c:1108
 __run_hrtimer kernel/time/hrtimer.c:1767 [inline]
 __hrtimer_run_queues+0x637/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_is_held_type+0x13e/0x190 kernel/locking/lockdep.c:5830
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc900001073a0 EFLAGS: 00000206
RAX: aa76e84596bff200 RBX: ffff888019e7bc00 RCX: aa76e84596bff200
RDX: ffff888019e7bc00 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80
RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000020e84 R12: 0000000000000004
R13: 0000000000000246 R14: ffffffff8e0c8858 R15: ffff888019e7c780
 lock_is_held include/linux/lockdep.h:288 [inline]
 neigh_flush_dev+0x198/0xa80 net/core/neighbour.c:394
 __neigh_ifdown+0x3d/0x460 net/core/neighbour.c:447
 neigh_ifdown+0x1f/0x30 net/core/neighbour.c:465
 rt6_disable_ip+0x730/0x7a0 net/ipv6/route.c:4948
 addrconf_ifdown+0x15e/0x1880 net/ipv6/addrconf.c:3825
 addrconf_notify+0x6c6/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 unregister_netdevice_many_notify+0xf36/0x1810 net/core/dev.c:11086
 ip_tunnel_delete_nets+0x31c/0x360 net/ipv4/ip_tunnel.c:1157
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x77f/0xb90 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
CPU: 0 PID: 5948 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:queued_write_lock_slowpath+0x125/0x294 kernel/locking/qrwlock.c:85
Code: f0 41 81 0e 00 01 00 00 42 0f b6 04 23 84 c0 74 37 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 2a 4c 89 f7 e8 bf be 6b f7 eb 20 f3 90 <42> 0f b6 04 23 84 c0 74 15 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 08
RSP: 0018:ffffc90000007520 EFLAGS: 00000206
RAX: 00000000000001ff RBX: 1ffffffff1c19108 RCX: ffffffff8a713fab
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8e0c8840
RBP: ffffc900000075d0 R08: ffffffff8e0c8843 R09: 1ffffffff1c19108
R10: dffffc0000000000 R11: fffffbfff1c19109 R12: dffffc0000000000
R13: 1ffff92000000ea8 R14: ffffffff8e0c8840 R15: ffffc90000007570
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff9a586058 CR3: 000000000cb30000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 queued_write_lock include/asm-generic/qrwlock.h:101 [inline]
 do_raw_write_lock+0x1ee/0x260 kernel/locking/spinlock_debug.c:210
 ___neigh_create+0xe5c/0x2440 net/core/neighbour.c:683
 ip6_finish_output2+0x159e/0x1650 net/ipv6/ip6_output.c:132
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ndisc_send_skb+0xbed/0x14b0 net/ipv6/ndisc.c:513
 addrconf_rs_timer+0x2bc/0x600 net/ipv6/addrconf.c:4006
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xddf/0x1130 kernel/smp.c:855
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 6a d7 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 a5 d3 0a 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 89 d3
RSP: 0018:ffffc90003287760 EFLAGS: 00000293
RAX: ffffffff817abd37 RBX: 1ffff110171e826d RCX: ffff88802bd81e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900032878e0 R08: ffffffff90d94537 R09: 1ffffffff21b28a6
R10: dffffc0000000000 R11: fffffbfff21b28a7 R12: ffff8880b8f41368
R13: dffffc0000000000 R14: ffff8880b8e3d148 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:990 [inline]
 flush_tlb_mm_range+0x41e/0x690 arch/x86/mm/tlb.c:1078
 tlb_flush arch/x86/include/asm/tlb.h:20 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:458 [inline]
 tlb_flush_mmu+0x1b7/0x4f0 mm/mmu_gather.c:299
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
 exit_mmap+0x3f0/0xb50 mm/mmap.c:3315
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1da/0x2c0 kernel/exit.c:569
 do_exit+0x88e/0x23c0 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f950958f749
Code: Unable to access opcode bytes at 0x7f950958f71f.
RSP: 002b:00007ffe54963f98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f950958f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 000000085496408f R09: 00007f95097b4280
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f95097b4280 R14: 0000000000000003 R15: 00007ffe54964050
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
RIP: 0010:do_raw_spin_lock+0xc/0x2c0 kernel/locking/spinlock_debug.c:113
Code: 07 80 c1 03 38 c1 7c 95 48 89 df e8 8e b6 74 00 eb 8b 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 <41> 55 41 54 53 48 83 e4 e0 48 81 ec 80 00 00 00 48 89 fb 65 48 8b
RSP: 0018:ffffc900001f0be0 EFLAGS: 00000096
RAX: aa76e84596bff200 RBX: ffffffff9712bda0 RCX: aa76e84596bff200
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff9712bda0
RBP: ffffc900001f0bf0 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000000802 R15: 1ffff9200003e180
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003c80 CR3: 0000000076cbd000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162
 debug_object_activate+0x6c/0x4b0 lib/debugobjects.c:709
 debug_hrtimer_activate kernel/time/hrtimer.c:450 [inline]
 debug_activate kernel/time/hrtimer.c:505 [inline]
 enqueue_hrtimer+0x30/0x370 kernel/time/hrtimer.c:1108
 __run_hrtimer kernel/time/hrtimer.c:1767 [inline]
 __hrtimer_run_queues+0x637/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_is_held_type+0x13e/0x190 kernel/locking/lockdep.c:5830
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc900001073a0 EFLAGS: 00000206
RAX: aa76e84596bff200 RBX: ffff888019e7bc00 RCX: aa76e84596bff200
RDX: ffff888019e7bc00 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80
RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000020e84 R12: 0000000000000004
R13: 0000000000000246 R14: ffffffff8e0c8858 R15: ffff888019e7c780
 lock_is_held include/linux/lockdep.h:288 [inline]
 neigh_flush_dev+0x198/0xa80 net/core/neighbour.c:394
 __neigh_ifdown+0x3d/0x460 net/core/neighbour.c:447
 neigh_ifdown+0x1f/0x30 net/core/neighbour.c:465
 rt6_disable_ip+0x730/0x7a0 net/ipv6/route.c:4948
 addrconf_ifdown+0x15e/0x1880 net/ipv6/addrconf.c:3825
 addrconf_notify+0x6c6/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x197/0x390 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 unregister_netdevice_many_notify+0xf36/0x1810 net/core/dev.c:11086
 ip_tunnel_delete_nets+0x31c/0x360 net/ipv4/ip_tunnel.c:1157
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x77f/0xb90 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>