rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4987/1:b..l rcu: (detected by 0, t=10503 jiffies, g=201329, q=2245 ncpus=2) task:udevd state:R running task stack:22776 pid:4987 tgid:4987 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7552 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:unwind_next_frame+0xfd/0x2550 arch/x86/kernel/unwind_orc.c:498 Code: 1f c6 05 4a 56 a4 0e 01 48 c7 c7 40 a3 c9 8b be 4a 03 00 00 48 c7 c2 80 a3 c9 8b e8 fd 67 2b 00 48 89 6c 24 38 48 89 5c 24 40 <49> 8d 5e 50 48 89 d8 48 c1 e8 03 48 89 44 24 28 42 80 3c 20 00 74 RSP: 0018:ffffc90002e8f360 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff81b105c9 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8c291100 RDI: ffffffff8c2910c0 RBP: 1ffff920005d1e88 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90002e8f458 R11: ffffffff81b10630 R12: dffffc0000000000 R13: ffffffff8176a21f R14: ffffc90002e8f408 R15: 1ffff920005d1e81 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:1397 [inline] __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938 __slab_free+0x274/0x2c0 mm/slub.c:5672 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:4610 [inline] slab_alloc_node mm/slub.c:4939 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x312/0x750 mm/slub.c:5347 _kmalloc_noprof include/linux/slab.h:973 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 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+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb025511b0a RSP: 002b:00007fffc7e42188 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000055f87a2e5fa0 RCX: 00007fb025511b0a RDX: 00007fffc7e42190 RSI: 000055f87a2e5fa0 RDI: 00000000ffffff9c RBP: 000055f87a2d4bf0 R08: 00063478c1c69200 R09: 3fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffc7e42190 R13: 000055f857714100 R14: 0000000000000001 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10515 jiffies! g201329 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:28408 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0x164/0x360 kernel/sched/core.c:7322 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 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: 3226 Comm: kworker/R-bat_e Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline] RIP: 0010:__rcu_read_unlock+0x32/0xe0 kernel/rcu/tree_plugin.h:435 Code: 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3d a9 a0 8e 11 48 8d 9f c4 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 4f ff 0b 75 1d 4c 8d b7 c8 04 00 00 4c 89 f0 48 c1 e8 03 RSP: 0018:ffffc90000a07238 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: ffff8880338961c4 RCX: 0000000080000302 RDX: ffffc90000a07301 RSI: ffffffff8c291100 RDI: ffff888033895d00 RBP: 1ffffffff2189601 R08: ffffc90000a073f0 R09: 0000000000000000 R10: ffffc90000a073b8 R11: fffff52000140e79 R12: 1ffff11006712c38 R13: ffffffff8176a21f R14: ffffc90000a07368 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff88812537c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5f7f5c0008 CR3: 0000000036250000 CR4: 00000000003526f0 Call Trace: rcu_read_unlock include/linux/rcupdate.h:873 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baf/0x2550 arch/x86/kernel/unwind_orc.c:709 __unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2700 [inline] slab_free mm/slub.c:6310 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6437 skb_ext_reset include/linux/skbuff.h:5119 [inline] skb_scrub_packet+0x2c8/0x3d0 net/core/skbuff.c:6278 ____dev_forward_skb include/linux/netdevice.h:4444 [inline] __dev_forward_skb2+0x28c/0x730 net/core/dev.c:2441 veth_forward_skb drivers/net/veth.c:323 [inline] veth_xmit+0x493/0xe60 drivers/net/veth.c:379 __netdev_start_xmit include/linux/netdevice.h:5387 [inline] netdev_start_xmit include/linux/netdevice.h:5396 [inline] xmit_one net/core/dev.c:3889 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905 __dev_queue_xmit+0x1435/0x37f0 net/core/dev.c:4872 dev_queue_xmit include/linux/netdevice.h:3436 [inline] br_dev_queue_push_xmit+0x370/0x4b0 net/bridge/br_forward.c:53 NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:318 br_nf_post_routing+0xa53/0xee0 net/bridge/br_netfilter_hooks.c:964 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:316 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1165 [inline] br_nf_forward_finish+0xa76/0xea0 net/bridge/br_netfilter_hooks.c:667 NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:318 br_nf_forward_ip+0x7eb/0xa30 net/bridge/br_netfilter_hooks.c:721 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:316 __br_forward+0x397/0x540 net/bridge/br_forward.c:115 br_handle_frame_finish+0x1175/0x1990 net/bridge/br_input.c:229 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6093 __netif_receive_skb_one_core net/core/dev.c:6204 [inline] __netif_receive_skb net/core/dev.c:6319 [inline] process_backlog+0x706/0x1860 net/core/dev.c:6670 __napi_poll+0xaa/0x330 net/core/dev.c:7729 napi_poll net/core/dev.c:7792 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7949 handle_softirqs+0x225/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_local_purge+0x2c1/0x340 net/batman-adv/translation-table.c:1363 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3557 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 rescuer_thread+0x7b6/0x10b0 kernel/workqueue.c:3621 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 net_ratelimit: 15462 callbacks suppressed bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! bridge0: received packet on veth1_to_bridge with own address as source address (addr:6e:0d:97:e0:f7:ba, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge!