rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5968/1:b..l P3072/1:b..l rcu: (detected by 0, t=10502 jiffies, g=14137, q=607 ncpus=2) task:kworker/u8:9 state:R running task stack:24280 pid:3072 tgid:3072 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893 Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 fa e4 df 10 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 RSP: 0018:ffffc9000b7f7818 EFLAGS: 00000206 RAX: a28664295fb1ac00 RBX: 0000000000000202 RCX: a28664295fb1ac00 RDX: 0000000000000003 RSI: ffffffff8d977b3e RDI: ffffffff8bc07ae0 RBP: ffff888030356728 R08: ffffffff8b243600 R09: ffffffff8df419e0 R10: dffffc0000000000 R11: ffffed100b926117 R12: 0000000000000003 R13: 0000000000000003 R14: ffffffff8df419e0 R15: ffff888030355b80 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:778 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:833 [inline] batadv_iv_ogm_schedule+0x715/0xf00 net/batman-adv/bat_iv_ogm.c:873 batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1709 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261 process_scheduled_works kernel/workqueue.c:3344 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425 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 task:syz-executor state:R running task stack:19496 pid:5968 tgid:5968 ppid:5960 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 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 14 17 e0 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900037868f8 EFLAGS: 00000206 RAX: e3ea645610a24200 RBX: 0000000000000000 RCX: e3ea645610a24200 RDX: 00000000d5b96fb2 RSI: ffffffff8d977b3e RDI: ffffffff8bc07ae0 RBP: ffffffff82644c7c R08: ffffffff82644c7c R09: ffffffff8df419e0 R10: dffffc0000000000 R11: ffffed102808a024 R12: 0000000000000002 R13: ffffffff8df419e0 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] kernfs_root+0x38/0x230 fs/kernfs/kernfs-internal.h:75 kernfs_activate fs/kernfs/dir.c:1426 [inline] kernfs_add_one+0x29d/0x5c0 fs/kernfs/dir.c:837 __kernfs_create_file+0x22b/0x2e0 fs/kernfs/file.c:1086 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x667/0x1170 fs/sysfs/group.c:189 internal_create_groups fs/sysfs/group.c:229 [inline] sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255 device_add_groups drivers/base/core.c:2836 [inline] device_add_attrs+0x1c4/0x5a0 drivers/base/core.c:2911 device_add+0x496/0xb80 drivers/base/core.c:3643 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2358 register_netdevice+0x1246/0x1a70 net/core/dev.c:11392 cfg80211_register_netdevice+0x138/0x2d0 net/wireless/core.c:1534 ieee80211_if_add+0xe50/0x1370 net/mac80211/iface.c:2337 ieee80211_register_hw+0x35d9/0x4110 net/mac80211/main.c:1607 mac80211_hwsim_new_radio+0x2f76/0x5320 drivers/net/wireless/virtual/mac80211_hwsim.c:5810 hwsim_new_radio_nl+0xf5b/0x1bd0 drivers/net/wireless/virtual/mac80211_hwsim.c:6504 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:728 __sock_sendmsg net/socket.c:743 [inline] __sys_sendto+0x3ce/0x540 net/socket.c:2212 __do_sys_sendto net/socket.c:2219 [inline] __se_sys_sendto net/socket.c:2215 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2215 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: 0033:0x7f58a23915dc RSP: 002b:00007ffed5960ab0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f58a3114620 RCX: 00007f58a23915dc RDX: 0000000000000024 RSI: 00007f58a3114670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffed5960b04 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f58a3114670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10586 jiffies! g14137 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:27240 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6115 Comm: syz.1.28 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline] RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:212 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 32 6e 55 03 66 RSP: 0018:ffffc90000a08e50 EFLAGS: 00000046 RAX: 0000000000045072 RBX: ffff8880b8723e40 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 0000000000045072 RDI: 0000000000000838 RBP: 0000000000000000 R08: ffffffff81af6a25 R09: ffffffff998e1508 R10: 0000000000000003 R11: ffffffff81718b10 R12: 0000000010004eda R13: dffffc0000000000 R14: 0000000000045072 R15: 0000000000000020 FS: 00007f147c65d6c0(0000) GS:ffff888125f37000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcd4aa7d68 CR3: 000000002859a000 CR4: 00000000003526f0 Call Trace: apic_write arch/x86/include/asm/apic.h:409 [inline] lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:418 clockevents_program_event+0x1c9/0x350 kernel/time/clockevents.c:334 hrtimer_interrupt+0x620/0xaa0 kernel/time/hrtimer.c:1916 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 1a b9 40 f6 48 89 df e8 52 30 41 f6 e8 9d 9b 6b f6 fb bf 01 00 00 00 f2 1f 33 f6 65 8b 05 ab a0 20 07 85 c0 74 07 5b e9 d1 4b 00 00 RSP: 0018:ffffc90002fc7c60 EFLAGS: 00000286 RAX: 49b59a66fc0f3c00 RBX: ffff88802f311280 RCX: 49b59a66fc0f3c00 RDX: 0000000000000000 RSI: ffffffff8d791132 RDI: 0000000000000001 RBP: 0000000000000011 R08: ffffffff8f820377 R09: 1ffffffff1f0406e R10: dffffc0000000000 R11: fffffbfff1f0406f R12: 1ffff11005e622a3 R13: 0000000000000000 R14: 0000000004000000 R15: ffff88802f311518 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x11a7/0x1340 kernel/signal.c:3037 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f147b78f749 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:00007f147c65d0e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007f147b9e5fa8 RCX: 00007f147b78f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f147b9e5fa8 RBP: 00007f147b9e5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f147b9e6038 R14: 00007ffea0a4e420 R15: 00007ffea0a4e508