rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=e004/1/0x4000000000000000 softirq=13562/13563 fqs=2 rcu: (detected by 1, t=10503 jiffies, g=12777, q=466 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5910 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:kasan_check_range+0x1c3/0x290 mm/kasan/generic.c:187 Code: 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 0e 41 80 3b 00 75 6b 49 ff c3 49 ff cc 75 f2 5b 41 5c 41 5d 41 5e 41 5f 5d 45 84 ff 0f 85 91 00 00 00 41 f7 c7 00 ff 00 00 0f 85 89 00 00 RSP: 0018:ffffc90000007878 EFLAGS: 00000056 RAX: 0000000000000001 RBX: 000000000000006b RCX: ffffffff8168ac57 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911eb508 RBP: ffffc90000007ac8 R08: ffffffff911eb50f R09: 1ffffffff223d6a1 R10: dffffc0000000000 R11: fffffbfff223d6a2 R12: 00000000d4c9f0e4 R13: ffff888029750000 R14: 0000000022e098f3 R15: ffff888029750b58 FS: 00005555607f3500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000300 CR3: 000000005ce02000 CR4: 00000000003506f0 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hlock_class kernel/locking/lockdep.c:228 [inline] __lock_acquire+0x1077/0x7d80 kernel/locking/lockdep.c:5133 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5756 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 debug_object_activate+0x6c/0x500 lib/debugobjects.c:747 debug_hrtimer_activate kernel/time/hrtimer.c:450 [inline] debug_activate kernel/time/hrtimer.c:504 [inline] enqueue_hrtimer+0x34/0x380 kernel/time/hrtimer.c:1100 __run_hrtimer kernel/time/hrtimer.c:1771 [inline] __hrtimer_run_queues+0x62f/0xc10 kernel/time/hrtimer.c:1818 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:mod_delayed_work_on+0x16f/0x1c0 kernel/workqueue.c:2053 Code: 2f 00 eb 1c e8 a2 97 2f 00 eb 15 e8 9b 97 2f 00 e8 26 57 39 09 4d 85 ff 74 e3 e8 8c 97 2f 00 fb 49 bf 00 00 00 00 00 fc ff df <31> ff 89 de e8 28 9b 2f 00 85 db 0f 95 c0 48 c7 44 24 20 0e 36 e0 RSP: 0018:ffffc900046a7280 EFLAGS: 00000293 RAX: ffffffff8157f3c4 RBX: 0000000000000000 RCX: ffff888029750000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900046a7338 R08: ffffffff911eb50f R09: 1ffffffff223d6a1 R10: dffffc0000000000 R11: fffffbfff223d6a2 R12: 0000000000000000 R13: 0000000000000008 R14: 1ffff920008d4e54 R15: dffffc0000000000 mod_delayed_work include/linux/workqueue.h:594 [inline] addrconf_mod_dad_work+0x76/0x120 net/ipv6/addrconf.c:331 inet6_addr_add+0x79e/0xb30 net/ipv6/addrconf.c:3079 inet6_rtm_newaddr+0x6fd/0x9d0 net/ipv6/addrconf.c:5043 rtnetlink_rcv_msg+0x843/0xf90 net/core/rtnetlink.c:6484 netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x4a9/0x6b0 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f31a495e98e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007ffc84d1ece8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00005555607f3500 RCX: 00007f31a495e98e RDX: 0000000000000040 RSI: 00007f31a5754670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffc84d1ed64 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f31a5754670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10493 jiffies! g12777 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27848 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 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: CPU: 1 PID: 147 Comm: kworker/u4:5 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline] RIP: 0010:smp_call_function_many_cond+0xd85/0x1190 kernel/smp.c:855 Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 34 01 0b 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 6f fd 0a 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 53 fd RSP: 0018:ffffc90002d3f780 EFLAGS: 00000293 RAX: ffffffff817c8dfd RBX: 1ffff110171c87a5 RCX: ffff88801abe0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002d3f900 R08: ffffffff911eb507 R09: 1ffffffff223d6a0 R10: dffffc0000000000 R11: fffffbfff223d6a1 R12: ffff8880b8e43d28 R13: ffff8880b8f3d380 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00003a8e1f065000 CR3: 000000000cf32000 CR4: 00000000003506e0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2222 [inline] text_poke_bp_batch+0x31e/0x980 arch/x86/kernel/alternative.c:2432 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207 static_key_enable+0x1a/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xa8/0x260 mm/kfence/core.c:847 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 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