rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29/4:b..l P6527/3:b..l rcu: (detected by 0, t=10502 jiffies, g=14453, q=1660 ncpus=2) task:syz.0.169 state:R running task stack:26120 pid:6527 tgid:6523 ppid:5796 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7235 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__sanitizer_cov_trace_pc+0x6b/0x80 kernel/kcov.c:235 Code: 40 16 00 00 83 fa 02 75 21 48 8b 91 48 16 00 00 48 8b 32 48 8d 7e 01 8b 89 44 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 cc cc cc cc cc 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 RSP: 0018:ffffc90005c4f1d8 EFLAGS: 00000287 RAX: ffffffff88f8056e RBX: 0000000000000100 RCX: 0000000000080000 RDX: ffffc900049f9000 RSI: 000000000004ead3 RDI: 000000000004ead4 RBP: ffffc90005c4f450 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1ed4797 R12: 0000000000000000 R13: dffffc0000000000 R14: 000000000000010e R15: ffff888033ede280 skb_reset_mac_len include/linux/skbuff.h:2991 [inline] __netif_receive_skb_core+0x26e/0x31a0 net/core/dev.c:5961 __netif_receive_skb_list_core+0x24d/0x810 net/core/dev.c:6239 __netif_receive_skb_list net/core/dev.c:6306 [inline] netif_receive_skb_list_internal+0x995/0xcf0 net/core/dev.c:6397 netif_receive_skb_list+0x55/0x4b0 net/core/dev.c:6449 xdp_recv_frames net/bpf/test_run.c:269 [inline] xdp_test_run_batch net/bpf/test_run.c:350 [inline] bpf_test_run_xdp_live+0x1946/0x1cf0 net/bpf/test_run.c:379 bpf_prog_test_run_xdp+0x81c/0x1160 net/bpf/test_run.c:1397 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4722 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2fec0bc799 RSP: 002b:00007f2fea316028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f2fec335fa0 RCX: 00007f2fec0bc799 RDX: 0000000000000050 RSI: 0000200000000140 RDI: 000000000000000a RBP: 00007f2fec152c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2fec336038 R14: 00007f2fec335fa0 R15: 00007ffd999c4968 task:ktimers/1 state:R running task stack:23800 pid:29 tgid:29 ppid:2 task_flags:0x4208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7185 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x57/0x2e0 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5260 [inline] __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5272 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] cfg80211_inform_single_bss_data+0x952/0x1bd0 net/wireless/scan.c:2344 cfg80211_inform_bss_data+0x266/0x3c40 net/wireless/scan.c:3226 cfg80211_inform_bss_frame_data+0x3c7/0x760 net/wireless/scan.c:3317 ieee80211_bss_info_update+0x794/0xa40 net/mac80211/scan.c:230 ieee80211_scan_rx+0x552/0xa40 net/mac80211/scan.c:364 __ieee80211_rx_handle_packet net/mac80211/rx.c:5305 [inline] ieee80211_rx_list+0x29fe/0x3740 net/mac80211/rx.c:5588 ieee80211_rx_napi+0x1b1/0x3e0 net/mac80211/rx.c:5611 ieee80211_rx include/net/mac80211.h:5267 [inline] ieee80211_handle_queued_frames+0xe8/0x1e0 net/mac80211/main.c:452 tasklet_action_common+0x2bf/0x540 kernel/softirq.c:925 handle_softirqs+0x1de/0x6f0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1138 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g14453 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=9700 rcu: rcu_preempt kthread starved for 10500 jiffies! g14453 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27776 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0x164/0x360 kernel/sched/core.c:7005 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+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 5e 5d 02 e9 13 c4 03 00 cc cc cc 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 53 9c 26 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8da07dc0 EFLAGS: 00000242 RAX: 00000000001dbdf1 RBX: ffffffff81995cca RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d5606f0 RDI: ffffffff8ba66600 RBP: ffffffff8da07eb0 R08: ffff8880b8833f1b R09: 1ffff110171067e3 R10: dffffc0000000000 R11: ffffed10171067e4 R12: ffffffff8f6a3cb0 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b605d8 FS: 0000000000000000(0000) GS:ffff88812633c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200001000000 CR3: 000000003e38a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ba/0x5d0 kernel/sched/idle.c:341 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:439 rest_init+0x2de/0x300 init/main.c:760 start_kernel+0x385/0x3d0 init/main.c:1210 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147