rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13/2:b..l rcu: (detected by 1, t=10502 jiffies, g=129389, q=799 ncpus=2) task:kworker/u8:1 state:R running task stack:23960 pid:13 tgid:13 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7183 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7364 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xff/0x120 kernel/softirq.c:457 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:912 [inline] __dev_queue_xmit+0xa04/0x4950 net/core/dev.c:4905 dev_queue_xmit include/linux/netdevice.h:3401 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip6_finish_output2+0xfd4/0x1ce0 net/ipv6/ip6_output.c:136 __ip6_finish_output+0x357/0xdf0 net/ipv6/ip6_output.c:208 ip6_finish_output net/ipv6/ip6_output.c:219 [inline] NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x2aa/0xa60 net/ipv6/ip6_output.c:246 dst_output include/net/dst.h:470 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK.constprop.0+0x115/0x5a0 include/linux/netfilter.h:312 mld_sendpack+0x8f7/0xec0 net/ipv6/mcast.c:1855 mld_send_initial_cr+0x219/0x320 net/ipv6/mcast.c:2271 ipv6_mc_dad_complete+0xa7/0x1d0 net/ipv6/mcast.c:2279 addrconf_dad_completed+0xd91/0xff0 net/ipv6/addrconf.c:4352 addrconf_dad_work+0x83c/0x1360 net/ipv6/addrconf.c:4280 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10528 jiffies! g129389 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7183 __schedule_loop kernel/sched/core.c:7262 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7277 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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: 18197 Comm: syz.3.3130 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:check_preemption_disabled+0x2b/0xe0 lib/smp_processor_id.c:19 Code: 54 55 53 48 83 ec 08 65 8b 1d 65 28 7e 08 65 f7 05 56 28 7e 08 ff ff ff 7f 74 0f 48 83 c4 08 89 d8 5b 5d 41 5c c3 cc cc cc cc <9c> 58 f6 c4 02 74 ea 65 4c 8b 25 1e 28 7e 08 48 89 fd 41 f6 44 24 RSP: 0018:ffffc9000344fc28 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e036a0d RDI: ffffffff8c1b6fe0 RBP: ffffffff82588b25 R08: 0000000000000001 R09: 00000000000001c8 R10: 0000000000000200 R11: 0000000000000000 R12: ffff88802fcc8000 R13: ffffffff82588b25 R14: 0000000000000283 R15: 0000000000000000 FS: 00007f4a0f45d6c0(0000) GS:ffff888124306000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff726b5d00 CR3: 000000009063e000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline] lock_release kernel/locking/lockdep.c:5888 [inline] lock_release+0x9a/0x310 kernel/locking/lockdep.c:5875 __might_fault+0x10c/0x140 mm/memory.c:7324 __clear_user arch/x86/include/asm/uaccess_64.h:183 [inline] clear_user arch/x86/include/asm/uaccess_64.h:207 [inline] copy_siginfo_to_user+0x83/0xc0 kernel/signal.c:3508 x64_setup_rt_frame+0xa03/0xce0 arch/x86/kernel/signal_64.c:194 setup_rt_frame arch/x86/kernel/signal.c:250 [inline] handle_signal arch/x86/kernel/signal.c:294 [inline] arch_do_signal_or_restart+0x59e/0x7a0 arch/x86/kernel/signal.c:339 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline] do_syscall_64+0x706/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4a0e59c817 Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 RSP: 002b:00007f4a0f45d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 00000000000000ca RBX: 00007f4a0e815fa8 RCX: 00007f4a0e59c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4a0e815fa8 RBP: 00007f4a0e815fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4a0e816038 R14: 00007fff24077520 R15: 00007fff24077608