rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11/2:b..l rcu: (detected by 1, t=10503 jiffies, g=17789, q=642 ncpus=2) task:kworker/u4:0 state:R running task stack:20936 pid:11 ppid:2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:stack_trace_consume_entry+0xa2/0x270 kernel/stacktrace.c:93 Code: cc 41 0f b6 04 17 84 c0 0f 85 73 01 00 00 44 89 23 b0 01 e9 99 00 00 00 31 c0 e9 92 00 00 00 48 89 f8 48 c1 e8 03 80 3c 10 00 <74> 29 49 89 ff 48 89 74 24 08 49 89 d4 4c 89 04 24 4c 89 cb e8 e5 RSP: 0018:ffffc90000107158 EFLAGS: 00000246 RAX: 1ffff92000020e4c RBX: ffffc9000010726c RCX: ffff888019e7bc00 RDX: dffffc0000000000 RSI: ffffffff8928e4a5 RDI: ffffc90000107260 RBP: 1ffff92000020e4e R08: ffffc90000107270 R09: 0000000000000007 R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000000 R13: 1ffff92000020e4d R14: ffffc90000107268 R15: 1ffff92000020e4d arch_stack_walk+0x138/0x190 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc+0xb4/0x240 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:721 [inline] neigh_alloc net/core/neighbour.c:495 [inline] ___neigh_create+0x6d2/0x2440 net/core/neighbour.c:649 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 ndisc_send_ns+0xcc/0x150 net/ipv6/ndisc.c:671 addrconf_dad_work+0xa25/0x14e0 net/ipv6/addrconf.c:4246 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 rcu: rcu_preempt kthread starved for 10547 jiffies! g17789 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:27752 pid:17 ppid:2 flags:0x00004000 Call Trace: 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:2167 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 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: 6995 Comm: syz.3.36 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:lock_release+0x5/0x8b0 kernel/locking/lockdep.c:5762 Code: 1b fa ff ff 48 89 df e8 e9 58 75 00 e9 0e fa ff ff bb 2f 00 00 00 e9 24 fa ff ff 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec e0 00 00 RSP: 0018:ffffc90003917bf0 EFLAGS: 00000282 RAX: bc5883a0fd8eac00 RBX: 00007ff4f295dca0 RCX: bc5883a0fd8eac00 RDX: 0000000000000000 RSI: ffffffff81c8ebfa RDI: ffff888021381e20 RBP: ffffc90003917d90 R08: dffffc0000000000 R09: 1ffffffff21b4ea6 R10: dffffc0000000000 R11: fffffbfff21b4ea7 R12: 00007ff4f295db38 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007ff4f295e6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 000000006095f000 CR4: 00000000003506f0 Call Trace: __clear_user arch/x86/include/asm/uaccess_64.h:167 [inline] clear_user arch/x86/include/asm/uaccess_64.h:191 [inline] copy_siginfo_to_user+0x5b/0xa0 kernel/signal.c:3374 x64_setup_rt_frame+0x740/0xcd0 arch/x86/kernel/signal_64.c:194 setup_rt_frame arch/x86/kernel/signal.c:223 [inline] handle_signal arch/x86/kernel/signal.c:267 [inline] arch_do_signal_or_restart+0x3e5/0x780 arch/x86/kernel/signal.c:312 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff4f1b8eba7 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007ff4f295e0e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007ff4f1dd5fa8 RCX: 00007ff4f1b8eba9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff4f1dd5fa8 RBP: 00007ff4f1dd5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff4f1dd6038 R14: 00007fff122a4c70 R15: 00007fff122a4d58