rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29915/1:b..l rcu: (detected by 0, t=10504 jiffies, g=123549, q=1909 ncpus=2) task:udevd state:R running task stack:27016 pid:29915 tgid:29915 ppid:5001 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] wp_page_copy mm/memory.c:3976 [inline] do_wp_page+0x3f15/0x4cc0 mm/memory.c:4336 handle_pte_fault mm/memory.c:6443 [inline] __handle_mm_fault mm/memory.c:6565 [inline] handle_mm_fault+0x1698/0x3170 mm/memory.c:6734 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f8eb20b5b69 RSP: 002b:00007fffe31dcb80 EFLAGS: 00010202 RAX: 00007f8eb21f21d0 RBX: 00005556a0c8b540 RCX: 00005556a0c8b540 RDX: 00005556a0c8b540 RSI: 00007f8eb21f21d0 RDI: 00005556a0c8b540 RBP: 00007f8eb21f1ac0 R08: 0000000000002760 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000049c0 R13: 00005556a0c8ff00 R14: 0000000000002020 R15: 00007f8eb21f1ac0 rcu: rcu_preempt kthread starved for 812 jiffies! g123549 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:27736 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 48 Comm: kworker/u8:3 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:kasan_check_range+0x9/0x2c0 mm/kasan/generic.c:199 Code: c6 a2 77 21 8e e8 c7 18 f7 fe 90 0f 0b cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 55 41 57 41 56 <41> 55 41 54 53 b0 01 48 85 f6 0f 84 ae 01 00 00 4c 8d 04 37 49 39 RSP: 0018:ffffc90000a08050 EFLAGS: 00000046 RAX: 1ffff1100541fc60 RBX: 0000000000000010 RCX: ffffffff8ba3085f RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffff88802a0fe308 RBP: 0000000000000000 R08: ffffffff903024f7 R09: 1ffffffff206049e R10: dffffc0000000000 R11: fffffbfff206049f R12: 0000000000000000 R13: ffff88802a0fe300 R14: ffff88802a0fe308 R15: ffff8880b8729030 FS: 0000000000000000(0000) GS:ffff88812539e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555586d014e8 CR3: 0000000028620000 CR4: 00000000003526f0 Call Trace: __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 rb_link_node include/linux/rbtree.h:96 [inline] __rb_add include/linux/rbtree.h:238 [inline] rb_add_linked include/linux/rbtree.h:281 [inline] timerqueue_linked_add+0x23f/0x2e0 lib/timerqueue.c:96 enqueue_hrtimer+0x18e/0x2c0 kernel/time/hrtimer.c:1117 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x10/0x90 kernel/kcov.c:300 Code: 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 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 58 66 72 11 <65> 8b 0d 79 66 72 11 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 RSP: 0018:ffffc90000a083f8 EFLAGS: 00000246 RAX: ffffffff8ba344f6 RBX: 00000000fffffffe RCX: 000000008ceb1b04 RDX: ffff88801af40000 RSI: 0000000000000054 RDI: 0000000000000000 RBP: ffffc90000a085b4 R08: ffff88801af40000 R09: 0000000000000008 R10: 0000000000000007 R11: 0000000000000100 R12: ffffffff8ceb1b40 R13: 0000000000000004 R14: ffffc90000a085b0 R15: 0000000000000054 string_nocheck lib/vsprintf.c:656 [inline] string+0x1d6/0x2b0 lib/vsprintf.c:737 vsnprintf+0x739/0xee0 lib/vsprintf.c:2948 nf_log_trace+0x26f/0x470 net/netfilter/nf_log.c:282 trace_packet+0x32b/0x4a0 net/ipv4/netfilter/ip_tables.c:209 ipt_do_table+0x105d/0x1630 net/ipv4/netfilter/ip_tables.c:306 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6202 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0xaa3/0x1950 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 spin_unlock_bh include/linux/spinlock.h:396 [inline] cfg80211_inform_single_bss_data+0x13b9/0x1af0 net/wireless/scan.c:2388 cfg80211_inform_bss_data+0x266/0x3c40 net/wireless/scan.c:3229 cfg80211_inform_bss_frame_data+0x3c7/0x730 net/wireless/scan.c:3320 ieee80211_bss_info_update+0x794/0xa40 net/mac80211/scan.c:230 ieee80211_rx_bss_info net/mac80211/ibss.c:1088 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1569 [inline] ieee80211_ibss_rx_queued_mgmt+0x1901/0x2cb0 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