rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (3 ticks this GP) idle=7214/1/0x4000000000000000 softirq=16053/16053 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=10925, q=493 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:153 [inline] RIP: 0010:lock_release+0x29a/0x3e0 kernel/locking/lockdep.c:5892 Code: c7 ab 15 9d 8d e8 26 67 ae 09 b8 ff ff ff ff 65 0f c1 05 f9 5a f4 10 83 f8 01 75 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b RSP: 0018:ffffc90000007c18 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000002 RCX: d669a6f6d3d6a000 RDX: 0000000000000005 RSI: ffffffff8d9d15ab RDI: ffffffff8bc074e0 RBP: ffff88801c2c0bf8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f70 R12: 0000000000000005 R13: 0000000000000005 R14: ffffffff99c12460 R15: ffff88801c2c0000 FS: 0000000000000000(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558046e50000 CR3: 0000000068b72000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:483 __run_hrtimer kernel/time/hrtimer.c:1745 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 eb 2c f4 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90000127078 EFLAGS: 00000206 RAX: d669a6f6d3d6a000 RBX: 0000000000000000 RCX: d669a6f6d3d6a000 RDX: 0000000000000000 RSI: ffffffff8d9d15ab RDI: ffffffff8bc074e0 RBP: ffffffff81731d25 R08: 0000000000000000 R09: ffffffff81731d25 R10: ffffc90000127238 R11: ffffffff81abbce0 R12: 0000000000000002 R13: ffffffff8e13d320 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4947 [inline] slab_alloc_node mm/slub.c:5246 [inline] kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5298 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] inet6_ifa_notify net/ipv6/addrconf.c:5610 [inline] __ipv6_ifa_notify+0x1e8/0xac0 net/ipv6/addrconf.c:6270 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline] addrconf_dad_completed+0x180/0xd60 net/ipv6/addrconf.c:4320 addrconf_dad_work+0xc36/0x14b0 net/ipv6/addrconf.c:-1 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g10925 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4729 rcu: rcu_preempt kthread starved for 10502 jiffies! g10925 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245