rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4982/1:b..l rcu: (detected by 0, t=10502 jiffies, g=278837, q=934 ncpus=1) task:udevd state:R running task stack:23480 pid:4982 tgid:4982 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:kasan_byte_accessible+0x1d/0x30 mm/kasan/generic.c:213 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 b8 00 00 00 00 00 fc ff df 48 c1 ef 03 48 01 c7 0f b6 07 3c 07 0f 96 c0 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 RSP: 0018:ffffc90003177428 EFLAGS: 00000297 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff81b823d1 RDI: fffffbfff1d7d000 RBP: ffffffff8ebe8000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90003177588 R11: 0000000000000000 R12: ffffffff81b823d1 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 __kasan_check_byte+0x13/0x50 mm/kasan/common.c:573 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire kernel/locking/lockdep.c:5842 [inline] lock_acquire+0x132/0x370 kernel/locking/lockdep.c:5825 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+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x3cd/0x7e0 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 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+0x79f/0x1090 mm/page_alloc.c:2950 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x2bf/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] tomoyo_encode2+0xfb/0x3c0 security/tomoyo/realpath.c:45 tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x18c/0x690 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x276/0x460 security/tomoyo/file.c:827 security_inode_getattr+0x116/0x280 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_statx_path fs/stat.c:299 [inline] vfs_statx+0x11f/0x3f0 fs/stat.c:356 vfs_fstatat+0x77/0xe0 fs/stat.c:373 __do_sys_newfstatat+0x9d/0x120 fs/stat.c:538 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f605fd11b0a RSP: 002b:00007ffef97449a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000563cafe62410 RCX: 00007f605fd11b0a RDX: 00007ffef97449b0 RSI: 0000563cafe502a8 RDI: 00000000ffffff9c RBP: 0000563cb9424148 R08: 00063478c1c69200 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffef97449b0 R14: 0000000000000000 R15: 00063478c1c69200 rcu: rcu_preempt kthread starved for 466 jiffies! g278837 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:27528 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: CPU: 0 UID: 0 PID: 3222 Comm: kworker/R-bat_e Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:pskb_may_pull_reason include/linux/skbuff.h:2867 [inline] RIP: 0010:pskb_may_pull include/linux/skbuff.h:2882 [inline] RIP: 0010:batadv_interface_tx+0x16a/0x1d00 net/batman-adv/mesh-interface.c:198 Code: 0f b6 14 02 48 89 c8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 cf 0a 00 00 44 8b 63 74 44 8b 6c 24 0c bf 0d 00 00 00 45 29 e5 <44> 89 ee e8 3e 4e 86 f6 41 83 fd 0d 0f 86 09 09 00 00 e8 bf 53 86 RSP: 0018:ffffc90000006e60 EFLAGS: 00000202 RAX: 0000000000000007 RBX: ffff888152f79780 RCX: ffff888152f797f4 RDX: 0000000000000000 RSI: ffffffff8b837b86 RDI: 000000000000000d RBP: ffff8880370cc000 R08: 0000000000000005 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000000002a R14: ffff8880370cc000 R15: ffff888152f797f0 FS: 0000000000000000(0000) GS:ffff888123df3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe0187619b7 CR3: 0000000033a94000 CR4: 00000000003526f0 Call Trace: __netdev_start_xmit include/linux/netdevice.h:5397 [inline] netdev_start_xmit include/linux/netdevice.h:5406 [inline] xmit_one net/core/dev.c:3889 [inline] dev_hard_start_xmit+0x121/0x760 net/core/dev.c:3905 __dev_queue_xmit+0x1bbf/0x4970 net/core/dev.c:4878 dev_queue_xmit include/linux/netdevice.h:3448 [inline] br_dev_queue_push_xmit+0x361/0x530 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] br_forward_finish+0x102/0x4d0 net/bridge/br_forward.c:66 br_nf_hook_thresh+0x30d/0x420 net/bridge/br_netfilter_hooks.c:1165 br_nf_forward_finish+0x693/0xb30 net/bridge/br_netfilter_hooks.c:667 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] br_nf_forward_arp net/bridge/br_netfilter_hooks.c:757 [inline] br_nf_forward+0x157a/0x19f0 net/bridge/br_netfilter_hooks.c:780 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK include/linux/netfilter.h:316 [inline] __br_forward+0x2f7/0x970 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xf0/0x180 net/bridge/br_forward.c:191 br_flood+0x29b/0x7b0 net/bridge/br_forward.c:245 br_handle_frame_finish+0x1014/0x1fa0 net/bridge/br_input.c:229 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline] br_handle_frame+0x97f/0x1540 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0x6c5/0x3530 net/core/dev.c:6103 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6214 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6329 process_backlog+0x37a/0x1580 net/core/dev.c:6680 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7739 napi_poll net/core/dev.c:7802 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:7959 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xac/0xe0 kernel/softirq.c:510 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2301 [inline] batadv_tt_purge+0x25d/0xbd0 net/batman-adv/translation-table.c:3566 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] rescuer_thread+0x905/0x14a0 kernel/workqueue.c:3629 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245