rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5923/1:b..l rcu: (detected by 1, t=10502 jiffies, g=10741, q=662 ncpus=2) task:syz-executor state:R running task stack:21544 pid:5923 ppid:5915 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 vprintk_emit+0x578/0x600 kernel/printk/printk.c:2342 _printk+0xd0/0x110 kernel/printk/printk.c:2366 batadv_check_known_mac_addr+0x2a7/0x3e0 net/batman-adv/hard-interface.c:528 batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998 notifier_call_chain+0x197/0x390 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline] call_netdevice_notifiers net/core/dev.c:2078 [inline] dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8948 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8962 do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860 __rtnl_newlink net/core/rtnetlink.c:3703 [inline] rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1e9dd90a7c RSP: 002b:00007ffe05870940 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f1e9eaf4620 RCX: 00007f1e9dd90a7c RDX: 000000000000002c RSI: 00007f1e9eaf4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffe05870994 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f1e9eaf4670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10553 jiffies! g10741 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:27752 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6027 Comm: syz.3.20 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4774 [inline] RIP: 0010:__lock_acquire+0x619/0x7c80 kernel/locking/lockdep.c:5087 Code: 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 00 55 da 90 be 08 00 00 00 e8 ff cb 75 00 48 0f a3 1d 57 49 73 0f <73> 1a 48 69 c3 d0 00 00 00 48 8d 98 c0 d3 70 90 49 b8 00 00 00 00 RSP: 0018:ffffc90000007880 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81670ba1 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90da5500 RBP: ffffc90000007ac8 R08: ffffffff90da5507 R09: 1ffffffff21b4aa0 R10: dffffc0000000000 R11: fffffbfff21b4aa1 R12: ffff88807d1046c4 R13: ffff88807d103c00 R14: 0000000000000002 R15: ffff88807d104728 FS: 0000555576509500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 000000002566d000 CR4: 00000000003506f0 Call Trace: lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x67/0x350 lib/debugobjects.c:764 debug_hrtimer_deactivate kernel/time/hrtimer.c:455 [inline] debug_deactivate+0x1d/0x1d0 kernel/time/hrtimer.c:511 __run_hrtimer kernel/time/hrtimer.c:1723 [inline] __hrtimer_run_queues+0x2bf/0xc40 kernel/time/hrtimer.c:1819 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 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: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 4a e0 ef f6 48 89 df e8 62 b2 f0 f6 e8 1d 51 14 f7 fb bf 01 00 00 00 b2 c9 e3 f6 65 8b 05 23 18 8c 75 85 c0 74 02 5b c3 e8 00 fa 88 RSP: 0018:ffffc90003657c98 EFLAGS: 00000282 RAX: d2d74677ecd48500 RBX: ffff8880568eae40 RCX: d2d74677ecd48500 RDX: dffffc0000000000 RSI: ffffffff8aaaba20 RDI: 0000000000000001 RBP: ffff8880568eb2d8 R08: ffffffff8e4a8f2f R09: 1ffffffff1c951e5 R10: dffffc0000000000 R11: fffffbfff1c951e6 R12: 1ffff1100ad1d65b R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x11f5/0x1400 kernel/signal.c:2905 arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f062878ebe9 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:00007ffdc4685998 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f06289c5fa0 RCX: 00007f062878ebe9 RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f0628811e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f06289c5fa0 R14: 00007f06289c5fa0 R15: 0000000000000004 sched: RT throttling activated