rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5141/1:b..l P6598/1:b..l rcu: (detected by 1, t=10503 jiffies, g=17073, q=863 ncpus=2) task:syz-executor state:R running task stack:21736 pid:6598 ppid:6594 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6891 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+0x29b/0x3e0 net/batman-adv/hard-interface.c:526 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:8936 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8950 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:2537 netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline] netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891 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: 0033:0x7f40933907bc RSP: 002b:00007ffce1af33e0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f40940e4620 RCX: 00007f40933907bc RDX: 000000000000002c RSI: 00007f40940e4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffce1af3434 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f40940e4670 R15: 0000000000000000 task:udevd state:R running task stack:25160 pid:5141 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xfa/0x110 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11f/0x190 kernel/sched/wait.c:213 sock_def_readable+0x1e1/0x430 net/core/sock.c:3329 __netlink_sendskb net/netlink/af_netlink.c:1270 [inline] netlink_sendskb+0x9b/0x130 net/netlink/af_netlink.c:1276 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595 ___sys_sendmsg+0x220/0x290 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685 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: 0033:0x7fcd102a7407 RSP: 002b:00007fffbec80f70 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fcd10a2b880 RCX: 00007fcd102a7407 RDX: 0000000000000000 RSI: 00007fffbec80fd0 RDI: 0000000000000004 RBP: 000055da2b51ef70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b3 R13: 000055da2b51e9e0 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10582 jiffies! g17073 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:27368 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 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: 7088 Comm: syz.3.101 Not tainted 6.6.95-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__list_add_valid_or_report+0x0/0xf0 lib/list_debug.c:25 Code: e1 80 e1 07 80 c1 03 38 c1 0f 8c 10 ff ff ff 4c 89 e7 e8 53 eb b7 fd e9 03 ff ff ff e8 e9 3b 5f fd 0f 0b cc cc cc cc cc cc cc 0f 1e fa 41 57 41 56 41 55 41 54 53 48 85 f6 0f 84 8a 00 00 00 RSP: 0018:ffffc90000007c70 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff88801e28f338 RCX: ffff88802bf2da00 RDX: ffff88801e28f338 RSI: ffff88801e28f338 RDI: ffff888077f2af50 RBP: ffff88801e28f340 R08: ffff88802bf2da00 R09: 0000000000000002 R10: 0000000000000001 R11: 0000000000010000 R12: ffff888077f2af50 R13: ffff88802bf2da00 R14: ffff88801e28f338 R15: 1ffff11003c51e68 FS: 00007f764c9936c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 00000000777db000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __list_add_valid include/linux/list.h:88 [inline] __list_add include/linux/list.h:150 [inline] list_add_tail include/linux/list.h:183 [inline] send_sigqueue+0x383/0x710 kernel/signal.c:2032 posix_timer_event kernel/time/posix-timers.c:299 [inline] posix_timer_fn+0x16e/0x3d0 kernel/time/posix-timers.c:325 __run_hrtimer kernel/time/hrtimer.c:1755 [inline] __hrtimer_run_queues+0x51e/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 fa 76 f7 f6 48 89 df e8 12 49 f8 f6 e8 ed f5 1b f7 fb bf 01 00 00 00 52 60 eb f6 65 8b 05 63 b6 93 75 85 c0 74 02 5b c3 e8 40 98 90 RSP: 0018:ffffc90004837c98 EFLAGS: 00000282 RAX: aab8586ab2a12d00 RBX: ffff88801c7b65c0 RCX: aab8586ab2a12d00 RDX: dffffc0000000000 RSI: ffffffff8aaab2c0 RDI: 0000000000000001 RBP: ffff88801c7b6a58 R08: ffffffff8e49ac2f R09: 1ffffffff1c93585 R10: dffffc0000000000 R11: fffffbfff1c93586 R12: 1ffff110038f6d4b 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: 0033:0x7f764bb8e929 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:00007f764c993038 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f764bdb5fa0 RCX: 00007f764bb8e929 RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f764bc10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f764bdb5fa0 R15: 00007fff431a3a18 sched: RT throttling activated