rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16919/1:b..l rcu: (detected by 1, t=10503 jiffies, g=96621, q=2281 ncpus=2) task:syz.9.2776 state:R running task stack:25752 pid:16919 tgid:16919 ppid:13012 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000410f338 EFLAGS: 00000206 RAX: e5aa4cf38d32b300 RBX: 0000000000000000 RCX: e5aa4cf38d32b300 RDX: 00000000951bad47 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff81742f85 R08: ffffffff81742f85 R09: ffffffff8e13f2e0 R10: ffffc9000410f4f8 R11: ffffffff81ad9d50 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 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+0xbc8/0xd30 mm/page_alloc.c:2943 __slab_free+0x21b/0x2a0 mm/slub.c:6008 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 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:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5319 alloc_task_struct_node kernel/fork.c:189 [inline] dup_task_struct+0x57/0x9a0 kernel/fork.c:918 copy_process+0x4ea/0x3950 kernel/fork.c:2056 kernel_clone+0x21e/0x820 kernel/fork.c:2655 __do_sys_clone3 kernel/fork.c:2957 [inline] __se_sys_clone3+0x256/0x2d0 kernel/fork.c:2936 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9bc43c3e89 RSP: 002b:00007fff70929068 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f9bc43462a0 RCX: 00007f9bc43c3e89 RDX: 00007f9bc43462a0 RSI: 0000000000000058 RDI: 00007fff709290b0 RBP: 00007f9bc514f6c0 R08: 00007f9bc514f6c0 R09: 00007fff70929197 R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8 R13: 000000000000006e R14: 00007fff709290b0 R15: 00007fff70929198 rcu: rcu_preempt kthread starved for 1600 jiffies! g96621 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:26456 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 64 Comm: kworker/u8:4 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:unwind_next_frame+0xeb2/0x23d0 arch/x86/kernel/unwind_orc.c:-1 Code: 4c 8b 64 24 48 74 08 48 89 df e8 59 24 b4 00 48 8b 44 24 18 48 89 03 ba 10 00 00 00 4c 89 e7 31 f6 e8 22 26 b4 00 48 8b 14 24 ca 04 00 00 4c 89 64 24 18 4d 8d 6e 08 4c 89 e8 48 c1 e8 03 48 RSP: 0018:ffffc90000a07cf8 EFLAGS: 00000246 RAX: ffffc90000a07e18 RBX: ffffc90000a07e00 RCX: 0000000000000000 RDX: ffffffff9036bb70 RSI: 0000000000000000 RDI: ffffc90000a07e28 RBP: dffffc0000000000 R08: ffffc90000a07e27 R09: 0000000000000000 R10: ffffc90000a07e18 R11: fffff52000140fc5 R12: ffffc90000a07e18 R13: 1ffff92000140fbb R14: ffffc90000a07dc8 R15: ffffc90000a07e10 FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe71d8bbac CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 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+0x46/0x50 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:2540 [inline] slab_free mm/slub.c:6674 [inline] kmem_cache_free+0x197/0x620 mm/slub.c:6785 skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1107 skb_release_all net/core/skbuff.c:1182 [inline] __kfree_skb net/core/skbuff.c:1196 [inline] consume_skb+0x9e/0xf0 net/core/skbuff.c:1428 nft_synproxy_eval_v6+0x376/0x560 net/netfilter/nft_synproxy.c:91 nft_synproxy_do_eval+0x3d7/0x570 net/netfilter/nft_synproxy.c:145 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6138 [inline] __netif_receive_skb+0xd3/0x380 net/core/dev.c:6251 process_backlog+0x622/0x1500 net/core/dev.c:6603 __napi_poll+0xae/0x320 net/core/dev.c:7667 napi_poll net/core/dev.c:7730 [inline] net_rx_action+0x672/0xe50 net/core/dev.c:7882 handle_softirqs+0x27d/0x850 kernel/softirq.c:626 do_softirq+0xec/0x180 kernel/softirq.c:523 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] cfg80211_inform_single_bss_data+0x12a7/0x1ad0 net/wireless/scan.c:2389 cfg80211_inform_bss_data+0x203/0x3b40 net/wireless/scan.c:3228 cfg80211_inform_bss_frame_data+0x3c7/0x710 net/wireless/scan.c:3319 ieee80211_bss_info_update+0x749/0x9e0 net/mac80211/scan.c:230 ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1575 [inline] ieee80211_ibss_rx_queued_mgmt+0xa5d/0x2af0 net/mac80211/ibss.c:1602 ieee80211_iface_process_skb net/mac80211/iface.c:1736 [inline] ieee80211_iface_work+0x85f/0x12d0 net/mac80211/iface.c:1790 cfg80211_wiphy_work+0x2ab/0x450 net/wireless/core.c:438 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246