rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P30/3:b..l P6128/1:b..l rcu: (detected by 1, t=10502 jiffies, g=19801, q=976 ncpus=2) task:kworker/1:7 state:D stack:21560 pid:6128 tgid:6128 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: wg-crypt-wg1 wg_packet_decrypt_worker Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x16d9/0x5700 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule_rtlock+0x30/0x70 kernel/sched/core.c:7426 rtlock_slowlock_locked+0x35c9/0x3c20 kernel/locking/rtmutex.c:1895 rtlock_slowlock kernel/locking/rtmutex.c:1922 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x165/0x400 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:45 [inline] tasklet_lock_callback kernel/softirq.c:909 [inline] tasklet_action_common+0xc5/0x600 kernel/softirq.c:959 handle_softirqs+0x1da/0x6d0 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] __local_bh_enable_ip+0x16f/0x2b0 kernel/softirq.c:325 local_bh_enable include/linux/bottom_half.h:33 [inline] spin_unlock_bh include/linux/spinlock_rt.h:122 [inline] ptr_ring_consume_bh include/linux/ptr_ring.h:399 [inline] wg_packet_decrypt_worker+0x30c/0xd90 drivers/net/wireguard/receive.c:499 process_one_work kernel/workqueue.c:3387 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551 kthread+0x38b/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 task:ksoftirqd/1 state:R running task stack:20280 pid:30 tgid:30 ppid:2 task_flags:0x4208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x16d9/0x5700 kernel/sched/core.c:7270 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7449 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 class_preempt_destructor include/linux/preempt.h:500 [inline] raw_spin_unlock_irqrestore_wake include/linux/sched/wake_q.h:102 [inline] rtlock_slowlock kernel/locking/rtmutex.c:1923 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x31a/0x400 kernel/locking/spinlock_rt.c:57 spin_lock_bh include/linux/spinlock_rt.h:90 [inline] cfg80211_inform_single_bss_data+0xc22/0x1bf0 net/wireless/scan.c:2405 cfg80211_inform_bss_data+0x263/0x3cc0 net/wireless/scan.c:3266 cfg80211_inform_bss_frame_data+0x3c7/0x840 net/wireless/scan.c:3358 ieee80211_bss_info_update+0x791/0xa50 net/mac80211/scan.c:230 ieee80211_scan_rx+0x552/0xa40 net/mac80211/scan.c:364 __ieee80211_rx_handle_packet net/mac80211/rx.c:5427 [inline] ieee80211_rx_list+0x2d23/0x3b40 net/mac80211/rx.c:5720 ieee80211_rx_napi+0x1ad/0x3d0 net/mac80211/rx.c:5743 ieee80211_rx include/net/mac80211.h:5449 [inline] ieee80211_handle_queued_frames+0xe4/0x1d0 net/mac80211/main.c:452 tasklet_action_common+0x31c/0x600 kernel/softirq.c:970 handle_softirqs+0x1da/0x6d0 kernel/softirq.c:645 run_ksoftirqd+0x53/0x190 kernel/softirq.c:1108 smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160 kthread+0x38b/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: rcu_preempt kthread starved for 1568 jiffies! g19801 f0x0 RCU_GP_WAIT_FQS(5) ->state=I ->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:25176 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x16d9/0x5700 kernel/sched/core.c:7270 preempt_schedule_notrace+0x56/0x90 kernel/sched/core.c:7542 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 class_preempt_notrace_destructor include/linux/preempt.h:501 [inline] trace_event_raw_event_lock+0x241/0x280 include/trace/events/lock.h:49 __do_trace_lock_release include/trace/events/lock.h:68 [inline] trace_lock_release include/trace/events/lock.h:68 [inline] lock_release+0x38e/0x3c0 kernel/locking/lockdep.c:5897 rcu_lock_release include/linux/rcupdate.h:319 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] class_rcu_destructor include/linux/rcupdate.h:1192 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 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 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4586 [inline] slab_alloc_node mm/slub.c:4919 [inline] kmem_cache_alloc_noprof+0x35d/0x660 mm/slub.c:4933 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x163/0x600 lib/debugobjects.c:420 debug_objects_fill_pool+0x63/0x80 lib/debugobjects.c:780 __debug_object_init+0x34/0x350 lib/debugobjects.c:792 timer_init_key_on_stack+0x3c/0x110 kernel/time/timer.c:816 schedule_timeout+0x140/0x2c0 kernel/time/sleep_timeout.c:96 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6143 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:206 Code: 89 fb e8 23 00 00 00 48 8b 3d 34 e6 f1 0b 48 89 de 5b e9 43 26 60 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0d c8 65 dd 10 65 48 8b 15 c8 65 RSP: 0018:ffffc900047cead0 EFLAGS: 00000002 RAX: 0000000000000020 RBX: 000000000000000b RCX: 0000000000000005 RDX: ffffffff81c7ead5 RSI: ffffffff8e226a20 RDI: 000000000000000b RBP: 0000000000000430 R08: ffff888030cabe80 R09: 0000000000000020 R10: 0000000000000100 R11: 000000000000001f R12: dffffc0000000000 R13: 0000000000000430 R14: ffff88803fa28440 R15: 000000000000fe2b FS: 00007fc39a0e1880(0000) GS:ffff888125bea000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe22d61ff8 CR3: 000000004d9ba000 CR4: 00000000003526f0 Call Trace: rb_event_length+0x345/0x400 kernel/trace/ring_buffer.c:213 rb_read_data_buffer+0xe2/0x5b0 kernel/trace/ring_buffer.c:1918 check_buffer+0x288/0x860 kernel/trace/ring_buffer.c:4742 __rb_reserve_next+0x549/0xdd0 kernel/trace/ring_buffer.c:4843 rb_reserve_next_event kernel/trace/ring_buffer.c:4980 [inline] ring_buffer_lock_reserve+0xc0d/0x10c0 kernel/trace/ring_buffer.c:5039 __trace_buffer_lock_reserve kernel/trace/trace.h:1676 [inline] trace_event_buffer_lock_reserve+0x1d4/0x700 kernel/trace/trace.c:1924 trace_event_buffer_reserve+0x1ef/0x2d0 kernel/trace/trace_events.c:715 do_trace_event_raw_event_rcu_utilization include/trace/events/rcu.h:27 [inline] trace_event_raw_event_rcu_utilization+0xe0/0x190 include/trace/events/rcu.h:27 __do_trace_rcu_utilization include/trace/events/rcu.h:27 [inline] trace_rcu_utilization+0x1c6/0x1f0 include/trace/events/rcu.h:27 rcu_note_context_switch+0x6e/0xe70 kernel/rcu/tree_plugin.h:330 __schedule+0x28f/0x5700 kernel/sched/core.c:7124 preempt_schedule_notrace+0x56/0x90 kernel/sched/core.c:7542 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 class_preempt_notrace_destructor include/linux/preempt.h:501 [inline] trace_event_raw_event_lock_acquire+0x271/0x2e0 include/trace/events/lock.h:23 __do_trace_lock_acquire include/trace/events/lock.h:23 [inline] trace_lock_acquire include/trace/events/lock.h:23 [inline] lock_acquire+0x300/0x350 kernel/locking/lockdep.c:5849 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1192 [inline] unwind_next_frame+0xac/0x2550 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 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4586 [inline] slab_alloc_node mm/slub.c:4919 [inline] kmem_cache_alloc_noprof+0x35d/0x660 mm/slub.c:4933 seq_open+0x62/0x140 fs/seq_file.c:64 kernfs_fop_open+0x576/0xcf0 fs/kernfs/file.c:-1 do_dentry_open+0x849/0x1420 fs/open.c:996 vfs_open+0x3b/0x350 fs/open.c:1101 do_open fs/namei.c:4837 [inline] path_openat+0x1448/0x1d60 fs/namei.c:5000 do_file_open+0x23e/0x4a0 fs/namei.c:5029 do_sys_openat2+0x115/0x200 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc39a1cf407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffe22d5c190 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc39a0e1880 RCX: 00007fc39a1cf407 RDX: 0000000000080000 RSI: 00007ffe22d5c310 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055cde30397f5 R13: 000055cde30397f5 R14: 0000000000000001 R15: 000055cde3054140