rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5888/1:b..l rcu: (detected by 0, t=10504 jiffies, g=35201, q=1479809 ncpus=2) task:kworker/0:4 state:R running task stack:21704 pid:5888 tgid:5888 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: mld mld_ifc_work Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 a1 67 14 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 8b f2 9d 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 58 d2 94 RSP: 0018:ffffc9000465f1d8 EFLAGS: 00000286 RAX: c04878345e8d3f00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000868c72fb RSI: ffffffff8e247e65 RDI: ffffffff8c2892e0 RBP: ffffffff81770256 R08: ffffffff81770256 R09: ffffffff8e95cce0 R10: ffffc9000465f338 R11: ffffffff81b0f560 R12: 0000000000000002 R13: ffffffff8e95cce0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495 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:1394 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2935 __slab_free+0x274/0x2c0 mm/slub.c:5608 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 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:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] __do_kmalloc_node mm/slub.c:5294 [inline] __kmalloc_node_track_caller_noprof+0x493/0x7b0 mm/slub.c:5403 kmalloc_reserve net/core/skbuff.c:635 [inline] __alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713 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: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 rcu: rcu_preempt kthread starved for 595 jiffies! g35201 f0x2 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 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: 5849 Comm: syz-executor 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:__debug_check_no_obj_freed lib/debugobjects.c:1109 [inline] RIP: 0010:debug_check_no_obj_freed+0x229/0x550 lib/debugobjects.c:1146 Code: 03 80 3c 10 00 74 12 4c 89 ff e8 c2 67 75 fd 48 ba 00 00 00 00 00 fc ff df 4d 8b 3f 4d 39 ef 0f 92 c0 4d 39 fc 0f 96 c1 08 c1 <75> 90 4c 8d 6d 10 4c 89 e8 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 da RSP: 0018:ffffc9000439f5d8 EFLAGS: 00000002 RAX: 1ffff11010e38600 RBX: 0000000000000028 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc9000439f540 RBP: ffff8880871c3770 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000873ea8 R12: ffff8880801f6000 R13: ffff8880801f5000 R14: 1ffff11010e386ee R15: ffff8880871e6950 FS: 000055558fea4500(0000) GS:ffff888125325000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558febfa28 CR3: 00000000659b0000 CR4: 00000000003526f0 Call Trace: __free_pages_prepare mm/page_alloc.c:1401 [inline] __free_frozen_pages+0x593/0xd30 mm/page_alloc.c:2935 __slab_free+0x274/0x2c0 mm/slub.c:5608 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5295 [inline] __kmalloc_noprof+0x35c/0x760 mm/slub.c:5307 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x12b/0x310 security/security.c:1895 vfs_getattr+0x23/0x70 fs/stat.c:259 vfs_statx_path+0x2b/0x230 fs/stat.c:299 vfs_statx+0x12e/0x200 fs/stat.c:356 vfs_fstatat+0x11b/0x170 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532 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: 0033:0x7f440a19ae5a Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 c7 c2 e8 ff ff ff f7 RSP: 002b:00007f440a53ecb8 EFLAGS: 00000286 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00007f440a232048 RCX: 00007f440a19ae5a RDX: 00007f440a53ece0 RSI: 00007f440a53ed70 RDI: 00000000ffffff9c RBP: 00007f440a53ed70 R08: 00007f440a53fd70 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000286 R12: 00007f440a53fe00 R13: 00007f440a232048 R14: 000000000003539b R15: 00007f440a53fe40