rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18231/3:b..l P11689/3:b..l rcu: (detected by 0, t=10503 jiffies, g=121365, q=200 ncpus=2) task:kworker/1:0 state:R running task stack:24376 pid:11689 tgid:11689 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: mld mld_ifc_work Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0xaf/0x350 kernel/locking/lockdep.c:5844 Code: 3d f5 37 8f 0e 00 0f 84 ce 00 00 00 65 8b 05 d8 c3 97 11 85 c0 0f 85 bf 00 00 00 65 48 8b 05 20 7e 97 11 83 b8 8c 0b 00 00 00 <0f> 85 aa 00 00 00 4c 89 74 24 10 4d 89 fe 9c 41 5f fa 48 c7 c7 c5 RSP: 0018:ffffc9000406f5b0 EFLAGS: 00000246 RAX: ffff888054a9bd80 RBX: 0000000000000000 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8a5f260e RDI: 1ffffffff1d2b9ac RBP: ffffffff8a5f25ee R08: 0000000000000000 R09: 0000000000000000 R10: 00000000fffffff5 R11: 0000000000000000 R12: 0000000000000002 R13: ffffffff8e95cd60 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] ipv6_chk_mcast_addr+0x4e/0x860 net/ipv6/mcast.c:1045 ip6_finish_output2+0xec7/0x13e0 net/ipv6/ip6_output.c:87 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246 dst_output include/net/dst.h:470 [inline] NF_HOOK+0x177/0x4f0 include/linux/netfilter.h:318 mld_sendpack+0x8b4/0xe40 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x835/0xe70 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:modprobe state:R running task stack:25288 pid:18231 tgid:18231 ppid:14744 task_flags:0x400000 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] filemap_map_pages+0x1a2a/0x2100 mm/filemap.c:3942 do_fault_around mm/memory.c:5851 [inline] do_read_fault mm/memory.c:5884 [inline] do_fault mm/memory.c:6027 [inline] do_pte_missing+0x1f38/0x33f0 mm/memory.c:4550 handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault mm/memory.c:6549 [inline] handle_mm_fault+0x1bd7/0x3170 mm/memory.c:6718 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f3e72b04890 RSP: 002b:00007fffd7099b50 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10490 jiffies! g121365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=74577 rcu: rcu_preempt kthread starved for 10491 jiffies! g121365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27832 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18228 Comm: syz.2.2277 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:lookup_object lib/debugobjects.c:438 [inline] RIP: 0010:debug_object_deactivate+0xaa/0x3a0 lib/debugobjects.c:892 Code: 89 ef e8 39 5b 74 fd 4d 8b 6d 00 c7 44 24 0c 00 00 00 00 41 bc 00 00 00 00 4d 85 ed 74 49 45 31 e4 eb 0c 4d 8b 6d 00 41 ff c4 <4d> 85 ed 74 38 49 8d 5d 18 48 89 dd 48 c1 ed 03 42 80 7c 35 00 00 RSP: 0018:ffffc90000a08d80 EFLAGS: 00000002 RAX: 1ffff1100ad56550 RBX: ffff888056ab2a98 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000a08ce0 RBP: 1ffff1100ad56553 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014119c R12: 0000000000000001 R13: ffff888055807070 R14: dffffc0000000000 R15: ffff888079175300 FS: 00007f5ded1966c0(0000) GS:ffff88812538d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5dec3ea540 CR3: 000000005a099000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:1898 [inline] __hrtimer_run_queues+0x23a/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unix_dgram_sendmsg+0x9cf/0x18d0 net/unix/af_unix.c:2242 Code: 48 8b 44 24 78 0f b6 18 89 de 83 e6 01 31 ff e8 f7 19 77 f7 83 e3 01 0f 85 de 04 00 00 48 8b 84 24 f0 00 00 00 42 80 3c 30 00 <74> 08 4c 89 e7 e8 77 54 e2 f7 49 83 3c 24 00 74 38 48 8b 54 24 58 RSP: 0018:ffffc9000386f700 EFLAGS: 00000246 RAX: 1ffff1100ab17347 RBX: 0000000000000000 RCX: 0000000000000002 RDX: ffff88802eb78000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000386f8d0 R08: ffff88807e3e08e7 R09: 1ffff1100fc7c11c R10: dffffc0000000000 R11: ffffed100fc7c11d R12: ffff8880558b9a38 R13: 1ffff9200070df00 R14: dffffc0000000000 R15: 0000000000000000 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841 __do_sys_sendmmsg net/socket.c:2868 [inline] __se_sys_sendmmsg net/socket.c:2865 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5dec39ce59 Code: 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 01 48 RSP: 002b:00007f5ded196028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f5dec615fa0 RCX: 00007f5dec39ce59 RDX: 0400000000000041 RSI: 0000200000000000 RDI: 0000000000000004 RBP: 00007f5dec432d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5dec616038 R14: 00007f5dec615fa0 R15: 00007ffe50f62fa8