rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16547/1:b..l rcu: (detected by 0, t=10503 jiffies, g=56401, q=746 ncpus=2) task:syz.4.5136 state:R running task stack:28720 pid:16547 tgid:16546 ppid:5851 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 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/0x8b0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0xd47/0x2550 arch/x86/kernel/unwind_orc.c:610 Code: 49 c1 ef 03 41 0f b6 04 2f 84 c0 0f 85 52 12 00 00 0f b6 76 01 83 e6 07 83 fe 04 0f 84 50 04 00 00 83 fe 03 0f 84 f5 01 00 00 <83> fe 02 0f 85 b2 07 00 00 4c 89 7c 24 38 4d 8d 7e 08 4c 89 fd 48 RSP: 0018:ffffc900044bf738 EFLAGS: 00000297 RAX: 0000000000000000 RBX: ffffffff90c8ff03 RCX: ffffffff904bc628 RDX: ffffffff90c8fefe RSI: 0000000000000002 RDI: ffffffff8c28b880 RBP: dffffc0000000000 R08: 000000000000000c R09: ffffffff8e95cc20 R10: ffffc900044bf858 R11: ffffffff81b0e0e0 R12: ffffc900044bf940 R13: 1ffff92000897f01 R14: ffffc900044bf808 R15: 1ffffffff2191fe0 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+0xc1c/0xd30 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_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_noprof+0x35c/0x760 mm/slub.c:5308 kmalloc_noprof include/linux/slab.h:954 [inline] sk_prot_alloc+0xe7/0x210 net/core/sock.c:2252 sk_alloc+0x3a/0x390 net/core/sock.c:2308 __netlink_create+0x65/0x260 net/netlink/af_netlink.c:626 netlink_create+0x3ca/0x590 net/netlink/af_netlink.c:684 __sock_create+0x4b2/0x9d0 net/socket.c:1665 sock_create net/socket.c:1723 [inline] __sys_socket_create net/socket.c:1760 [inline] __sys_socket+0xd6/0x1b0 net/socket.c:1807 __do_sys_socket net/socket.c:1821 [inline] __se_sys_socket net/socket.c:1819 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1819 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: 0033:0x7f14d2f9ce59 RSP: 002b:00007f14d3d81028 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 00007f14d3215fa0 RCX: 00007f14d2f9ce59 RDX: 000000000000000c RSI: 0000000000000003 RDI: 0000000000000010 RBP: 00007f14d3032d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f14d3216038 R14: 00007f14d3215fa0 R15: 00007ffcfc5dab48 rcu: rcu_preempt kthread starved for 2604 jiffies! g56401 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 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: CPU: 0 UID: 0 PID: 8701 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 9d 28 f8 f5 f7 c3 00 02 00 00 74 05 e8 e0 c2 23 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 b4 a7 e9 f5 65 8b 05 ad de 8d 07 85 c0 74 18 5b 41 5e e9 51 48 RSP: 0018:ffffc90000007090 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000282 RCX: 0000000080000102 RDX: 0000000000000002 RSI: ffffffff8dfa4c5e RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff903033f7 R09: 1ffffffff206067e R10: dffffc0000000000 R11: fffffbfff206067f R12: ffff888047915af0 R13: ffff888047915a00 R14: ffffffff9a6c4138 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881252a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe6f4dffffc CR3: 0000000032e30000 CR4: 00000000003526f0 Call Trace: __debug_check_no_obj_freed lib/debugobjects.c:1135 [inline] debug_check_no_obj_freed+0x52e/0x550 lib/debugobjects.c:1156 slab_free_hook mm/slub.c:2620 [inline] slab_free mm/slub.c:6251 [inline] kmem_cache_free+0xfd/0x650 mm/slub.c:6378 netlink_broadcast_filtered+0xe18/0xf20 net/netlink/af_netlink.c:1540 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2598 br_fdb_update+0x4c8/0x690 net/bridge/br_fdb.c:1023 br_handle_frame_finish+0x573/0x1c80 net/bridge/br_input.c:144 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x91f/0xc30 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x374/0x6f0 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+0x1277/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x98f/0x3170 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+0x76d/0x1950 net/core/dev.c:6666 __napi_poll+0xae/0x340 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7953 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 ieee80211_rx_bss_info net/mac80211/ibss.c:1160 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1569 [inline] ieee80211_ibss_rx_queued_mgmt+0x1ac7/0x2cb0 net/mac80211/ibss.c:1596 ieee80211_iface_process_skb net/mac80211/iface.c:1795 [inline] ieee80211_iface_work+0x845/0x1380 net/mac80211/iface.c:1849 cfg80211_wiphy_work+0x2cf/0x460 net/wireless/core.c:513 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 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