rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16712/1:b..l rcu: (detected by 0, t=10503 jiffies, g=108821, q=1415 ncpus=2) task:syz.3.2988 state:R running task stack:26328 pid:16712 tgid:16710 ppid:5618 task_flags:0x40054c flags:0x00080003 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:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 bb ef 4e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 06 a2 16 0f 0f 82 ac 02 00 00 8b 35 ce d5 16 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d ef 4e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0018:ffffc9000345f628 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e137691 RDI: ffffffff8c3e9a80 RBP: ffffffff8e9e60c0 R08: 0000000069df47d5 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] page_ext_get+0x36/0x1a0 mm/page_ext.c:531 __reset_page_owner+0x2b/0x190 mm/page_owner.c:306 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:4612 [inline] slab_alloc_node mm/slub.c:4945 [inline] __do_kmalloc_node mm/slub.c:5361 [inline] __kmalloc_noprof+0x2bf/0x820 mm/slub.c:5387 _kmalloc_noprof include/linux/slab.h:973 [inline] _kzalloc_noprof include/linux/slab.h:1290 [inline] kobject_get_path+0xcf/0x2c0 lib/kobject.c:161 kobject_uevent_env+0x287/0x18b0 lib/kobject_uevent.c:548 __device_release_driver drivers/base/dd.c:1361 [inline] device_release_driver_internal+0x51d/0x620 drivers/base/dd.c:1372 driver_detach+0xd8/0x1b0 drivers/base/dd.c:1435 bus_remove_driver+0x13b/0x2e0 drivers/base/bus.c:832 driver_unregister+0x76/0xb0 drivers/base/driver.c:202 usb_gadget_unregister_driver+0x49/0x70 drivers/usb/gadget/udc/core.c:1757 raw_release+0x19b/0x260 drivers/usb/gadget/legacy/raw_gadget.c:463 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x951/0x2ae0 kernel/exit.c:1004 do_group_exit+0xd5/0x2a0 kernel/exit.c:1147 get_signal+0x1ec7/0x21e0 kernel/signal.c:3038 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f95b019caeb RSP: 002b:00007f95b10faf00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffffc RBX: 0000000000000006 RCX: 00007f95b019caeb RDX: 00007f95b10fbfd0 RSI: 0000000080085502 RDI: 0000000000000006 RBP: 00007f95b10fbfd0 R08: 00007f95b0064ba7 R09: 00007f95b10fafc8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502 R13: 0000000800000000 R14: 0000000000000008 R15: 00007f95b0251379 rcu: rcu_preempt kthread starved for 742 jiffies! g108821 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:27432 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 14 Comm: kworker/u8:1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:__find_rr_leaf+0xf0/0x1040 net/ipv6/route.c:850 Code: 00 00 e8 83 6f bd f7 4c 8d bb c0 00 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 0f 85 1f 0d 00 00 4c 8b b3 c0 00 00 00 4d 85 f6 <0f> 85 1a 06 00 00 e8 55 6f bd f7 4c 8d b3 df 00 00 00 4c 89 f0 4c RSP: 0018:ffffc90000a079a0 EFLAGS: 00000246 RAX: 1ffff110039daa18 RBX: ffff88801ced5000 RCX: ffffffff8a4c14c9 RDX: ffff88801ea8ca80 RSI: ffffffff8a4c109d RDI: ffff88801ea8ca80 RBP: ffff88801ced5064 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88801ced50c0 FS: 0000000000000000(0000) GS:ffff8881241e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8da9c96ff8 CR3: 0000000056b78000 CR4: 00000000003526f0 Call Trace: find_rr_leaf net/ipv6/route.c:893 [inline] rt6_select net/ipv6/route.c:937 [inline] fib6_table_lookup+0x50f/0xa10 net/ipv6/route.c:2255 ip6_pol_route+0x1d5/0x1310 net/ipv6/route.c:2292 pol_lookup_func include/net/ip6_fib.h:667 [inline] fib6_rule_lookup+0x52f/0x720 net/ipv6/fib6_rules.c:123 ip6_route_input_lookup net/ipv6/route.c:2363 [inline] ip6_route_input+0x662/0xc50 net/ipv6/route.c:2666 ip6_rcv_finish_core.isra.0+0x1b1/0x1260 net/ipv6/ip6_input.c:106 ip6_rcv_finish+0x130/0x300 net/ipv6/ip6_input.c:117 ip_sabotage_in+0x21e/0x290 net/bridge/br_netfilter_hooks.c:988 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] ipv6_rcv+0xa4/0x3d0 net/ipv6/ip6_input.c:351 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6206 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6319 netif_receive_skb_internal net/core/dev.c:6405 [inline] netif_receive_skb+0x139/0x7d0 net/core/dev.c:6464 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70 br_handle_frame_finish+0xa94/0x1fa0 net/bridge/br_input.c:235 br_nf_hook_thresh+0x30d/0x420 net/bridge/br_netfilter_hooks.c:1165 br_nf_pre_routing_finish_ipv6+0x659/0xdd0 net/bridge/br_netfilter_ipv6.c:153 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x39c/0x8b0 net/bridge/br_netfilter_ipv6.c:183 br_nf_pre_routing+0x90f/0x1560 net/bridge/br_netfilter_hooks.c:513 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0xce9/0x1540 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0x6c5/0x3530 net/core/dev.c:6093 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6204 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6319 process_backlog+0x37a/0x1580 net/core/dev.c:6670 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7729 napi_poll net/core/dev.c:7792 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:7949 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 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x5db/0x710 net/core/skbuff.c:699 alloc_skb include/linux/skbuff.h:1384 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline] nsim_dev_trap_report_work+0x2af/0xd20 drivers/net/netdevsim/dev.c:922 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 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 ip6_tunnel: ip6gre1 xmit: Local address not yet configured! net_ratelimit: 11094 callbacks suppressed bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, 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 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 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:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, vlan:0) net_ratelimit: 12558 callbacks suppressed bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, 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 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 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:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, vlan:0) bridge0: received packet on veth1_to_bridge with own address as source address (addr:12:74:fe:57:64:02, vlan:0)