rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14511/1:b..l (detected by 0, t=10503 jiffies, g=78985, q=498 ncpus=2) task:syz.4.3941 state:R running task stack:25728 pid:14511 ppid:11923 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 vprintk_emit+0x5c9/0x680 kernel/printk/printk.c:2304 _printk+0xcc/0x110 kernel/printk/printk.c:2328 batadv_check_known_mac_addr+0x2a7/0x3e0 net/batman-adv/hard-interface.c:527 batadv_hard_if_event+0x491/0x1550 net/batman-adv/hard-interface.c:992 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455 call_netdevice_notifiers_extack net/core/dev.c:2039 [inline] call_netdevice_notifiers net/core/dev.c:2053 [inline] dev_set_mac_address+0x2c4/0x3d0 net/core/dev.c:8886 dev_set_mac_address_user+0x2d/0x50 net/core/dev.c:8900 dev_ifsioc+0x770/0xe90 net/core/dev_ioctl.c:339 dev_ioctl+0x578/0xea0 net/core/dev_ioctl.c:588 sock_do_ioctl+0x222/0x2f0 net/socket.c:1218 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f380738e969 RSP: 002b:00007f3808215038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f38075b5fa0 RCX: 00007f380738e969 RDX: 0000200000000080 RSI: 0000000000008924 RDI: 0000000000000009 RBP: 00007f3807410ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f38075b5fa0 R15: 00007fff26129a98 rcu: rcu_preempt kthread starved for 10434 jiffies! g78985 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:27776 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 14518 Comm: syz.3.3944 Not tainted 6.1.136-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:get_stack_pointer arch/x86/include/asm/stacktrace.h:93 [inline] RIP: 0010:unwind_start arch/x86/include/asm/unwind.h:62 [inline] RIP: 0010:perf_callchain_kernel+0x2d7/0x5c0 arch/x86/events/core.c:2801 Code: 00 4d 8b 6d 00 31 ff 4c 89 ee e8 94 ce 7f 00 4d 85 ed 74 3e e8 aa ca 7f 00 eb 3f 4d 85 ed 49 bf 00 00 00 00 00 fc ff df 74 3f 94 ca 7f 00 4d 8d a5 98 00 00 00 4c 89 e0 48 c1 e8 03 42 80 3c RSP: 0018:ffffc900001dfae0 EFLAGS: 00000086 RAX: ffff88804ab0bb80 RBX: 1ffff9200003bf64 RCX: ffff88804ab0bb80 RDX: 0000000000010100 RSI: 0000000000000002 RDI: 0000000000000000 RBP: ffffc900001dfc10 R08: dffffc0000000000 R09: ffffc900001dfb40 R10: fffff5200003bf74 R11: 1ffff9200003bf68 R12: ffffc900001e0568 R13: ffffc900001e04d8 R14: 1ffff9200003bf8d R15: dffffc0000000000 FS: 00007f1d4c48e6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f712ff8 CR3: 0000000045b2d000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: get_perf_callchain+0x376/0x480 kernel/events/callchain.c:200 perf_callchain kernel/events/core.c:7489 [inline] perf_prepare_sample+0x375/0x1fd0 kernel/events/core.c:7522 __perf_event_output kernel/events/core.c:7707 [inline] perf_event_output_forward+0x163/0x2a0 kernel/events/core.c:7727 __perf_event_overflow+0x448/0x610 kernel/events/core.c:9473 perf_swevent_hrtimer+0x3af/0x500 kernel/events/core.c:10881 __run_hrtimer kernel/time/hrtimer.c:1691 [inline] __hrtimer_run_queues+0x4e8/0xc80 kernel/time/hrtimer.c:1755 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1817 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:ndisc_constructor+0xb1/0x8b0 net/ipv6/ndisc.c:342 Code: 7c 24 08 48 89 5c 24 10 4c 8d b8 d8 05 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 d4 ec f6 f8 4c 89 74 24 20 <4d> 8b 2f 48 8b 44 24 10 48 8d 58 10 49 89 dc 49 c1 ec 03 48 b8 00 RSP: 0018:ffffc900001e0580 EFLAGS: 00000246 RAX: 1ffff1100f1350bb RBX: ffff888054a29800 RCX: ceffa0a0b4599300 RDX: 0000000000000003 RSI: ffffffff8a6c0f80 RDI: ffffffff8abf0da0 RBP: 0000000000000017 R08: dffffc0000000000 R09: fffffbfff1bfd03e R10: fffffbfff1bfd03e R11: 1ffffffff1bfd03d R12: dffffc0000000000 R13: ffff88807af7a000 R14: ffff8880789a8000 R15: ffff8880789a85d8 ___neigh_create+0xcd7/0x24c0 net/core/neighbour.c:660 ip6_finish_output2+0x14f0/0x1590 net/ipv6/ip6_output.c:129 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x5d3/0xa60 net/ipv6/ip6_output.c:216 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbfb/0x1510 net/ipv6/ndisc.c:513 addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3982 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1820 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833 handle_softirqs+0x2a1/0x920 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:661 irq_exit_rcu+0x5/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:preempt_schedule_irq+0xac/0x150 kernel/sched/core.c:6873 Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 70 bf 01 00 00 00 e8 5f f3 3f f7 e8 da 79 6f f7 fb bf 01 00 00 00 bf b9 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24 RSP: 0018:ffffc90012a8f780 EFLAGS: 00000282 RAX: ceffa0a0b4599300 RBX: 0000000000000000 RCX: ceffa0a0b4599300 RDX: dffffc0000000000 RSI: ffffffff8a6bfe00 RDI: 0000000000000001 RBP: ffffc90012a8f830 R08: ffffffff8f7cd048 R09: ffffffff8f7cd058 R10: ffffffff8f7cd050 R11: ffffffff8f7cd043 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92002551ef0 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:do_dentry_open+0x2a9/0x10d0 fs/open.c:863 Code: ed 03 42 80 7c 25 00 00 74 08 48 89 df e8 9f cf f2 ff 4c 8b 33 4d 85 f6 0f 84 a1 00 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 f7 e8 7d cf f2 ff 49 8b 3e e8 a5 8d 8e ff 84 c0 0f 84 RSP: 0018:ffffc90012a8f8f0 EFLAGS: 00000246 RAX: 1ffffffff14f2f1c RBX: ffff88802597bc28 RCX: 0000000000080000 RDX: ffffc9001bbe9000 RSI: 000000000000014c RDI: 000000000000014d RBP: 1ffff11004b2f785 R08: dffffc0000000000 R09: ffffed1004b2f785 R10: ffffed1004b2f785 R11: 1ffff11004b2f784 R12: dffffc0000000000 R13: ffff88802597ba10 R14: ffffffff8a7978e0 R15: ffff888074fcf680 do_open fs/namei.c:3626 [inline] path_openat+0x25c6/0x2e70 fs/namei.c:3783 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810 do_sys_openat2+0x142/0x490 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1d4b58e969 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:00007f1d4c48e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1d4b7b5fa0 RCX: 00007f1d4b58e969 RDX: 0000000000000000 RSI: 0000200000000080 RDI: ffffffffffffff9c RBP: 00007f1d4b610ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1d4b7b5fa0 R15: 00007fffe1dc4208