rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4994/1:b..l rcu: (detected by 0, t=10503 jiffies, g=124237, q=2990 ncpus=2) task:udevd state:R running task stack:22808 pid:4994 tgid:4994 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 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:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 41 20 2c 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 2b 3b ca 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 10 21 2f 0a cc 48 8d 3d 78 d4 b8 RSP: 0018:ffffc900032270e0 EFLAGS: 00000282 RAX: 5e180350bca0c700 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000008010719e RSI: ffffffff8e4ae7b4 RDI: ffffffff8c4bd280 RBP: ffffffff8176f21f R08: ffffffff8176f21f R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c20 R12: 0000000000000002 R13: ffffffff8eb59c20 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xac/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:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 __slab_free+0x274/0x2c0 mm/slub.c:5767 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:4612 [inline] slab_alloc_node mm/slub.c:4945 [inline] __do_kmalloc_node mm/slub.c:5361 [inline] __kmalloc_noprof+0x311/0x720 mm/slub.c:5387 _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_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2739 do_dentry_open+0x4a0/0x1380 fs/open.c:924 vfs_open+0x3b/0x340 fs/open.c:1052 do_open fs/namei.c:4700 [inline] path_openat+0x2e44/0x3830 fs/namei.c:4859 do_file_open+0x23e/0x4a0 fs/namei.c:4888 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1385 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: 0033:0x7fd2b7ca7407 RSP: 002b:00007ffd83b244f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fd2b83fb880 RCX: 00007fd2b7ca7407 RDX: 0000000000080000 RSI: 00007ffd83b24670 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055ffadae77f5 R13: 000055ffadae77f5 R14: 0000000000000001 R15: 00007ffd83b28cc0 rcu: rcu_preempt kthread starved for 10232 jiffies! g124237 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 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: 3227 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:trace_lock_release include/trace/events/lock.h:68 [inline] RIP: 0010:lock_release+0x44/0x3c0 kernel/locking/lockdep.c:5879 Code: 8b 05 40 0c ca 11 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 43 0c ca 11 83 f8 08 0f 83 56 02 00 00 89 c0 48 0f a3 05 ec 17 b5 0e <73> 0d e8 25 f9 08 00 84 c0 0f 84 94 02 00 00 83 3d e6 4a b5 0e 00 RSP: 0018:ffffc90000a07698 EFLAGS: 00000297 RAX: 0000000000000001 RBX: ffffc90000a077b8 RCX: 0000000080000102 RDX: ffffc90000a07701 RSI: ffffffff8176f21f RDI: ffffffff8eb59c20 RBP: 1ffffffff21dab01 R08: ffffc9000d27ff38 R09: 0000000000000000 R10: ffffc90000a077f8 R11: fffff52000140f01 R12: ffffc9000d278000 R13: ffffffff8176f21f R14: ffffffff8eb59c20 R15: ffffc9000d27ff48 FS: 0000000000000000(0000) GS:ffff88812505a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000040000 CR3: 000000005b7ac000 CR4: 00000000003526f0 Call Trace: rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 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:2705 [inline] slab_free mm/slub.c:6405 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6532 skb_ext_del include/linux/skbuff.h:5100 [inline] nf_bridge_info_free net/bridge/br_netfilter_hooks.c:157 [inline] br_nf_dev_queue_xmit+0x4f6/0x2540 net/bridge/br_netfilter_hooks.c:856 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:1366 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3565 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 rescuer_thread+0x7b6/0x10b0 kernel/workqueue.c:3629 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: 11451 callbacks suppressed ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! net_ratelimit: 10772 callbacks suppressed ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1b advertised our address fe80::a8aa:aaff:feaa:aa1b on veth0_to_bridge!