rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5911/1:b..l rcu: (detected by 0, t=10502 jiffies, g=88773, q=818 ncpus=2) task:kworker/1:4 state:R running task stack:21032 pid:5911 tgid:5911 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: mld mld_ifc_work Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__asan_memset+0x24/0x50 mm/kasan/shadow.c:84 Code: 90 90 90 90 90 90 f3 0f 1e fa 55 41 56 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 e8 1e e5 ff ff 84 c0 <74> 11 4c 89 f7 89 ee 48 89 da 5b 41 5e 5d e9 69 c5 7f 09 31 c0 5b RSP: 0018:ffffc900050671f8 EFLAGS: 00000202 RAX: ffffc90005067801 RBX: 0000000000000010 RCX: ffffffff8176985e RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90005067338 RBP: 0000000000000000 R08: ffffc90005067347 R09: 1ffff92000a0ce68 R10: dffffc0000000000 R11: fffff52000a0ce69 R12: ffffc90005067338 R13: 1ffff92000a0ce5f R14: ffffc90005067338 R15: ffffc90005067330 unwind_next_frame+0xeae/0x23c0 arch/x86/kernel/unwind_orc.c:607 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 __slab_free+0x263/0x2b0 mm/slub.c:5573 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4918 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702 alloc_skb include/linux/skbuff.h:1383 [inline] mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025 mld_send_cr net/ipv6/mcast.c:2148 [inline] mld_ifc_work+0x6e6/0xe70 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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 10548 jiffies! g88773 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:27744 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 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+0x51e/0xb90 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: 18242 Comm: syz.2.2287 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:class_spinlock_irqsave_constructor include/linux/spinlock.h:618 [inline] RIP: 0010:posix_timer_fn+0x27/0x1c0 kernel/time/posix-timers.c:371 Code: 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 41 54 53 49 89 ff 49 bd 00 00 00 00 00 fc ff df e8 f0 62 10 00 49 8d 9f 28 ff ff ff <48> 89 df e8 51 f1 fc 09 49 89 c6 48 c7 c0 c0 09 12 90 48 c1 e8 03 RSP: 0018:ffffc90000a08d08 EFLAGS: 00000006 RAX: ffffffff81b55ce0 RBX: ffff8880783ce240 RCX: ffff88801dbe3d00 RDX: 0000000000010000 RSI: 0000000000000000 RDI: ffff8880783ce318 RBP: ffffc90000a08e88 R08: ffffffff9011d6b7 R09: 1ffffffff2023ad6 R10: dffffc0000000000 R11: ffffffff81b55cc0 R12: ffff8880783ce318 R13: dffffc0000000000 R14: ffffffff81b55cc0 R15: ffff8880783ce318 FS: 00007f03d11df6c0(0000) GS:ffff888125554000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000002540 CR3: 000000005cb00000 CR4: 0000000000350ef0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1785 [inline] __hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849 hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1911 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x460 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:handle_signal arch/x86/kernel/signal.c:-1 [inline] RIP: 0010:arch_do_signal_or_restart+0x117/0x830 arch/x86/kernel/signal.c:339 Code: c7 00 49 8b 04 24 48 89 44 24 08 41 89 c4 bf ff ff ff ff 4c 89 e6 e8 e8 81 5d 00 b8 ff ff ff ff 49 39 c4 75 51 e8 f9 7c 5d 00 cf 00 00 00 4c 89 f9 4c 8d 7b 78 4c 89 f8 48 c1 e8 03 80 3c 08 RSP: 0018:ffffc90003c8fd80 EFLAGS: 00000246 RAX: ffffffff816842d7 RBX: ffffc90003c8ff48 RCX: 0000000000080000 RDX: ffffc90003fe2000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90003c8fe90 R08: ffffffff9011d6b7 R09: 1ffffffff2023ad6 R10: dffffc0000000000 R11: fffffbfff2023ad7 R12: 00000000ffffffff R13: 1ffff92000791fb4 R14: ffff88801dbe3d00 R15: dffffc0000000000 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f03d039c817 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:00007f03d11df0e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f03d0615fa8 RCX: 00007f03d039c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f03d0615fa8 RBP: 00007f03d0615fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f03d0616038 R14: 00007ffecb664320 R15: 00007ffecb664408