rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4990/1:b..l rcu: (detected by 1, t=10503 jiffies, g=140697, q=1590 ncpus=2) task:klogd state:R running task stack:24392 pid:4990 tgid:4990 ppid:1 task_flags:0x400100 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1840/0x57a0 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8e0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:231 [inline] RIP: 0010:unwind_next_frame+0x254/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: ff c0 4a 8d 04 6d 00 00 00 00 4c 01 e8 48 8d 34 45 c8 68 ba 90 4b 8d 04 40 48 8d 04 45 c8 68 ba 90 48 3d 1e fd 6e 91 0f 97 c0 <48> 81 fe 1e fd 6e 91 0f 83 0e 04 00 00 49 bc 00 00 00 00 00 fc ff RSP: 0018:ffffc900049d7320 EFLAGS: 00000293 RAX: ffffffff90c80300 RBX: dffffc0000000000 RCX: 0000000080000000 RDX: 00000000000aa634 RSI: ffffffff90c80374 RDI: ffffffff8c289940 RBP: ffffffff81b07148 R08: 000000000002447e R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e95c780 R12: ffffffff9171bee8 R13: 0000000000024472 R14: ffffc900049d73c8 R15: 000000000000b071 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:5613 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:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_node_noprof+0x380/0x680 mm/slub.c:4951 __alloc_skb+0x1d7/0x7a0 net/core/skbuff.c:702 alloc_skb include/linux/skbuff.h:1385 [inline] alloc_skb_with_frags+0xc6/0x760 net/core/skbuff.c:6766 sock_alloc_send_pskb+0x878/0x990 net/core/sock.c:3007 unix_dgram_sendmsg+0x4da/0x17b0 net/unix/af_unix.c:2141 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x672/0x710 net/socket.c:2266 __do_sys_sendto net/socket.c:2273 [inline] __se_sys_sendto net/socket.c:2269 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2269 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: 0033:0x7f29c2140407 RSP: 002b:00007fffbc9e49e0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f29c1ff0c80 RCX: 00007f29c2140407 RDX: 000000000000005b RSI: 00007fffbc9e4b20 RDI: 0000000000000003 RBP: 00007fffbc9e4f50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007fffbc9e4f68 R13: 00007fffbc9e4b20 R14: 0000000000000040 R15: 00007fffbc9e4b20 rcu: rcu_preempt kthread starved for 9379 jiffies! g140697 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:26816 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1840/0x57a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 3234 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_dat_purge RIP: 0010:rcu_lockdep_current_cpu_online+0x0/0x120 kernel/rcu/tree.c:4033 Code: de e8 74 7f 42 03 e9 54 ff ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 65 8b 0d 00 c7 8b 11 b0 01 f7 c1 00 00 RSP: 0018:ffffc900000078a8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080000102 RDX: ffff888032ff0000 RSI: ffffffff8c289980 RDI: ffffffff8c289940 RBP: ffffc900000079f0 R08: ffff88809e5a1687 R09: 0000000000000000 R10: ffff88809e5a1668 R11: ffffed1013cb42d1 R12: 1ffff11013cb42df R13: ffff888025fe0800 R14: 0000000000000001 R15: ffff88809e5a1650 FS: 0000000000000000(0000) GS:ffff8881252b9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f67919ec4b8 CR3: 00000000349ec000 CR4: 00000000003526f0 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:113 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 br_port_get_rcu net/bridge/br_private.h:458 [inline] br_handle_frame+0x3b1/0x1510 net/bridge/br_input.c:361 __netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6089 __netif_receive_skb_one_core net/core/dev.c:6200 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0x706/0x1860 net/core/dev.c:6666 __napi_poll+0xaa/0x330 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7953 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_dat_purge net/batman-adv/distributed-arp-table.c:185 [inline] batadv_dat_purge+0x2d7/0x3c0 net/batman-adv/distributed-arp-table.c:204 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+0x389/0x470 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: 10821 callbacks suppressed bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) net_ratelimit: 11760 callbacks suppressed bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0) bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:1a:68:13:32:c8:fb, vlan:0)