wlan0: beacon TX faster than countdown (channel/color switch) completion rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5980 P2961/1:b..l rcu: (detected by 1, t=10502 jiffies, g=9089, q=1327 ncpus=2) task:kworker/u8:8 state:R running task stack:24520 pid:2961 tgid:2961 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_unbound cfg80211_wiphy_work Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0xea3/0x20a0 arch/x86/kernel/unwind_orc.c:664 Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 9e 0c 00 00 49 89 6d 40 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 27 0c 00 00 41 39 5d 00 0f 84 RSP: 0018:ffffc9000c287450 EFLAGS: 00000a02 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff912548dc RDX: 1ffff92001850e98 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffc9000c287508 R08: ffffffff912548e0 R09: 00000000ae4a951d R10: 0000000000000002 R11: 000000000000a961 R12: ffffc9000c287510 R13: ffffc9000c2874c0 R14: ffffc9000c2875f0 R15: ffffc9000c2874f4 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6663 [inline] kfree+0x2f8/0x6e0 mm/slub.c:6871 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1576 [inline] ieee80211_ibss_rx_queued_mgmt+0x1ab4/0x2fc0 net/mac80211/ibss.c:1602 ieee80211_iface_process_skb net/mac80211/iface.c:1736 [inline] ieee80211_iface_work+0xe28/0x1350 net/mac80211/iface.c:1790 cfg80211_wiphy_work+0x3fb/0x560 net/wireless/core.c:438 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 task:syz.2.11 state:R running task stack:26856 pid:5980 tgid:5974 ppid:5823 task_flags:0x400140 flags:0x00080000 Call Trace: sched_show_task kernel/sched/core.c:7819 [inline] sched_show_task+0x423/0x630 kernel/sched/core.c:7794 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall kernel/rcu/tree_stall.h:681 [inline] check_cpu_stall kernel/rcu/tree_stall.h:856 [inline] rcu_pending kernel/rcu/tree.c:3667 [inline] rcu_sched_clock_irq+0x2634/0x31f0 kernel/rcu/tree.c:2704 update_process_times+0x178/0x2d0 kernel/time/timer.c:2474 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x506/0x720 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x64e/0xc40 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:strncpy_from_kernel_nofault+0xf7/0x260 mm/maccess.c:97 Code: 00 00 00 e8 9b 81 c4 ff 4c 89 f6 4c 89 ef e8 a0 7b c4 ff 4d 39 f5 0f 8d b8 00 00 00 4c 89 fb e8 7f 81 c4 ff 45 31 ed 8a 45 00 <48> b9 00 00 00 00 00 fc ff df 41 89 c4 48 89 d8 48 89 da 48 c1 e8 RSP: 0018:ffffc9000496f7e8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffc9000496f848 RCX: ffffc90010492000 RDX: 0000000000080000 RSI: ffffffff81fa62f1 RDI: ffff8880341797d4 RBP: fffffffffffffffc R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffff888034178b30 R12: ffffc9000496f848 R13: fffffffffffffff2 R14: 0000000000000008 R15: fffffffffffffffc bpf_probe_read_kernel_str_common kernel/trace/bpf_trace.c:264 [inline] ____bpf_probe_read_kernel_str kernel/trace/bpf_trace.c:273 [inline] bpf_probe_read_kernel_str+0x26/0x70 kernel/trace/bpf_trace.c:270 bpf_prog_6c8a88f82979c0f2+0x4b/0x51 bpf_dispatcher_nop_func include/linux/bpf.h:1376 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x3d2/0xb50 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x1035/0x31a0 net/bpf/test_run.c:1158 bpf_prog_test_run kernel/bpf/syscall.c:4703 [inline] __sys_bpf+0x1035/0x4980 kernel/bpf/syscall.c:6182 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline] __se_sys_bpf kernel/bpf/syscall.c:6272 [inline] __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:6272 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffaf698f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffaf7831038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007ffaf6be6180 RCX: 00007ffaf698f749 RDX: 0000000000000050 RSI: 00002000000002c0 RDI: 000000000000000a RBP: 00007ffaf6a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffaf6be6218 R14: 00007ffaf6be6180 R15: 00007fffffa50008 rcu: rcu_preempt kthread starved for 10577 jiffies! g9089 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:28024 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 06 60 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 59 13 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 000000000019d46b RBX: 0000000000000000 RCX: ffffffff8b7706d9 RDX: 0000000000000000 RSI: ffffffff8dac1f05 RDI: ffffffff8bf23a80 RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000 R13: ffffffff8e097b40 R14: ffffffff9087fbd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124909000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555635325c8 CR3: 000000005e139000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3ef/0x4d0 init/main.c:1206 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148