rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4537/1:b..l (detected by 1, t=10503 jiffies, g=17189, q=319 ncpus=2) task:kworker/u4:14 state:R running task stack:25352 pid:4537 ppid:2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __local_bh_enable_ip+0x13b/0x1b0 kernel/softirq.c:428 spin_unlock_bh include/linux/spinlock.h:396 [inline] __fib6_clean_all+0x239/0x370 net/ipv6/ip6_fib.c:2268 rt6_sync_down_dev net/ipv6/route.c:4944 [inline] rt6_disable_ip+0x120/0x7f0 net/ipv6/route.c:4949 addrconf_ifdown+0x162/0x1a10 net/ipv6/addrconf.c:3798 addrconf_notify+0x405/0xf40 net/ipv6/addrconf.c:-1 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455 call_netdevice_notifiers_extack net/core/dev.c:2039 [inline] call_netdevice_notifiers net/core/dev.c:2053 [inline] dev_close_many+0x28d/0x400 net/core/dev.c:1601 unregister_netdevice_many+0x471/0x1840 net/core/dev.c:10964 unregister_netdevice_queue+0x31c/0x360 net/core/dev.c:10921 unregister_netdevice include/linux/netdevice.h:3075 [inline] nsim_destroy+0x49/0x150 drivers/net/netdevsim/netdev.c:382 __nsim_dev_port_del+0x155/0x1c0 drivers/net/netdevsim/dev.c:1433 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1445 [inline] nsim_dev_reload_destroy+0x283/0x480 drivers/net/netdevsim/dev.c:1662 nsim_dev_reload_down+0x86/0xb0 drivers/net/netdevsim/dev.c:968 devlink_reload+0x1f1/0x660 net/devlink/leftover.c:4472 devlink_pernet_pre_exit+0x116/0x270 net/devlink/leftover.c:12501 ops_pre_exit_list net/core/net_namespace.c:162 [inline] cleanup_net+0x57b/0xb80 net/core/net_namespace.c:620 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread starved for 9665 jiffies! g17189 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:26272 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5293 Comm: syz.5.183 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:lock_release+0x33/0x910 kernel/locking/lockdep.c:5670 Code: 55 41 54 53 48 83 e4 e0 48 81 ec e0 00 00 00 48 89 74 24 30 48 89 7c 24 10 65 48 8b 04 25 28 00 00 00 48 89 84 24 c0 00 00 00 <49> bd 00 00 00 00 00 fc ff df 48 c7 44 24 60 b3 8a b5 41 48 c7 44 RSP: 0018:ffffc90000007ca0 EFLAGS: 00000086 RAX: 66eb4a26f87b8900 RBX: 0000000000000001 RCX: ffff8880242b5940 RDX: 0000000000010000 RSI: ffffffff81509152 RDI: ffffffff8cb2a9e0 RBP: ffffc90000007da8 R08: dffffc0000000000 R09: fffffbfff215c249 R10: fffffbfff215c249 R11: 1ffffffff215c248 R12: 0000000000000001 R13: ffffffff81509152 R14: ffffffff8c9e2800 R15: dffffc0000000000 FS: 00007fb6321fd6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f47411a4000 CR3: 0000000078c57000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release include/linux/rcupdate.h:355 [inline] rcu_read_unlock include/linux/rcupdate.h:824 [inline] __sigqueue_alloc+0x2bd/0x520 kernel/signal.c:428 __send_signal_locked+0x22f/0xde0 kernel/signal.c:1129 do_send_sig_info kernel/signal.c:1301 [inline] group_send_sig_info+0x1f6/0x250 kernel/signal.c:1449 do_bpf_send_signal+0x7b/0x150 kernel/trace/bpf_trace.c:840 irq_work_single+0xd1/0x230 kernel/irq_work.c:211 irq_work_run_list kernel/irq_work.c:242 [inline] irq_work_run+0x152/0x2e0 kernel/irq_work.c:251 __sysvec_irq_work+0xba/0x350 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x98/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline] RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:206 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 9f bd f7 02 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc900035a7cb0 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: ffffffff8c5e3b88 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff520006b4f85 R10: fffff520006b4f85 R11: 1ffff920006b4f84 R12: ffff8880b8e33e01 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000020 arch_irq_work_raise+0x82/0xd0 arch/x86/kernel/irq_work.c:31 irq_work_queue+0x95/0x140 kernel/irq_work.c:114 bpf_send_signal_common+0x2b2/0x420 kernel/trace/bpf_trace.c:879 ____bpf_send_signal kernel/trace/bpf_trace.c:888 [inline] bpf_send_signal+0x15/0x20 kernel/trace/bpf_trace.c:886 bpf_prog_7ba5217f62dcd359+0x38/0x3c bpf_dispatcher_nop_func include/linux/bpf.h:1001 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 __bpf_trace_sys_enter+0x60/0x70 include/trace/events/syscalls.h:18 trace_sys_enter+0x6b/0x80 include/trace/events/syscalls.h:18 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb63132adb9 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007fb6321fcb40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007fb6315c6098 RCX: 00007fb63132adb9 RDX: 00007fb6321fcb40 RSI: 00007fb6321fcc70 RDI: 0000000000000011 RBP: 00007fb6315c6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb6315c6128 R14: 00007ffc7ffbcfb0 R15: 00007ffc7ffbd098