rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P48/1:b..l P13123/1:b..l rcu: (detected by 1, t=10503 jiffies, g=81125, q=178 ncpus=2) task:syz.9.1353 state:R running task stack:24424 pid:13123 ppid:10414 flags:0x00004000 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 __local_bh_enable_ip+0x13f/0x1c0 kernel/softirq.c:413 spin_unlock_bh include/linux/spinlock.h:396 [inline] __fib6_clean_all+0x23d/0x380 net/ipv6/ip6_fib.c:2267 fib6_flush_trees+0x12d/0x190 net/ipv6/ip6_fib.c:2290 rt_genid_bump_ipv6 include/net/net_namespace.h:543 [inline] add_addr+0x14c/0x2c0 net/ipv6/addrconf.c:3179 add_v4_addrs+0x70d/0xbc0 net/ipv6/addrconf.c:3236 addrconf_sit_config net/ipv6/addrconf.c:3487 [inline] addrconf_init_auto_addrs+0x39b/0xaa0 net/ipv6/addrconf.c:3525 addrconf_notify+0xb62/0x1010 net/ipv6/addrconf.c:3712 notifier_call_chain+0x197/0x390 kernel/notifier.c:93 call_netdevice_notifiers_mtu net/core/dev.c:2101 [inline] dev_set_mtu_ext+0x436/0x620 net/core/dev.c:8828 dev_set_mtu+0xb9/0x170 net/core/dev.c:8849 dev_ifsioc+0x53f/0xe20 net/core/dev_ioctl.c:536 dev_ioctl+0x7e2/0x1170 net/core/dev_ioctl.c:786 sock_do_ioctl+0x226/0x2f0 net/socket.c:1236 sock_ioctl+0x623/0x7a0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 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: 0033:0x7fda1118eec9 RSP: 002b:00007fda1209b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fda113e6270 RCX: 00007fda1118eec9 RDX: 0000200000002280 RSI: 0000000000008922 RDI: 0000000000000008 RBP: 00007fda11211f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fda113e6308 R14: 00007fda113e6270 R15: 00007fffed1af878 task:kworker/u4:3 state:R running task stack:21192 pid:48 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc90000b97a40 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 2a80bc0872219a00 RDX: 0000000000000000 RSI: ffffffff8aaace20 RDI: ffffffff8afc71c0 RBP: ffffc90000b97b48 R08: dffffc0000000000 R09: 1ffffffff21b4ca0 R10: dffffc0000000000 R11: fffffbfff21b4ca1 R12: 1ffff92000172f54 R13: ffffffff8cd2fe20 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xef/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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: rcu_preempt kthread starved for 10570 jiffies! g81125 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:27080 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: CPU: 1 PID: 13118 Comm: syz.0.1356 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:196 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 f3 0f 1e fa 89 f6 31 d2 e9 e7 e7 18 03 0f 1f 80 00 00 00 RSP: 0018:ffffc9000f9b7cd8 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: 0000000000000200 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: 0000000000000000 R08: ffffc9000f9b7c47 R09: 1ffff92001f36f88 R10: dffffc0000000000 R11: fffff52001f36f89 R12: ffff8880b8f35001 R13: dffffc0000000000 R14: ffff8880b8f35050 R15: 0000000000000020 FS: 00007f32ee9c36c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c279c5a CR3: 000000001d77f000 CR4: 00000000003506e0 Call Trace: __apic_send_IPI_self arch/x86/include/asm/apic.h:454 [inline] arch_irq_work_raise+0x68/0x70 arch/x86/kernel/irq_work.c:31 irq_work_queue+0x99/0x140 kernel/irq_work.c:124 bpf_send_signal_common+0x2b6/0x420 kernel/trace/bpf_trace.c:875 ____bpf_send_signal kernel/trace/bpf_trace.c:884 [inline] bpf_send_signal+0x19/0x20 kernel/trace/bpf_trace.c:882 bpf_prog_7ba5217f62dcd359+0x40/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 trace_sys_enter+0x69/0x80 include/trace/events/syscalls.h:18 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f32edb2af79 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007f32ee9c2b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007f32edde5fa8 RCX: 00007f32edb2af79 RDX: 00007f32ee9c2b40 RSI: 00007f32ee9c2c70 RDI: 0000000000000011 RBP: 00007f32edde5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f32edde6038 R14: 00007ffeebaf3ca0 R15: 00007ffeebaf3d88