rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=445/1/0x4000000000000000 softirq=33533/33537 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5800/1:b..l (detected by 1, t=10505 jiffies, g=45897, q=8) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12237 Comm: syz.0.1741 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] RIP: 0010:rcu_is_watching+0x56/0xa0 kernel/rcu/tree.c:1123 Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 70 82 58 00 48 c7 c3 08 b3 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 2b 8b 03 65 ff 0d b5 bf 9e 7e 74 08 24 01 5b 41 5e 41 5f RSP: 0018:ffffc90000007b40 EFLAGS: 00000802 RAX: 0000000000000000 RBX: ffff8880b903b308 RCX: 52cca3877e381000 RDX: 0000000000000000 RSI: ffffffff8a59a860 RDI: ffffffff8a59a820 RBP: ffffc90000007c70 R08: dffffc0000000000 R09: fffffbfff1ad334e R10: fffffbfff1ad334e R11: 1ffffffff1ad334d R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff8bbc3820 R15: dffffc0000000000 FS: 00007f4f672176c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c38c108 CR3: 000000001ecc3000 CR4: 00000000003506f0 Call Trace: trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0xba/0x870 kernel/locking/lockdep.c:5634 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_unlock_irqrestore+0x6d/0x100 kernel/locking/spinlock.c:194 __run_hrtimer kernel/time/hrtimer.c:1681 [inline] __hrtimer_run_queues+0x441/0xc40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] RIP: 0010:rcu_is_watching+0x36/0xa0 kernel/rcu/tree.c:1123 Code: e8 1f ae 45 08 89 c3 83 f8 08 73 5c 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 20 38 bc 8b 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 70 82 58 00 48 c7 c3 08 b3 03 00 49 03 1e 48 89 RSP: 0018:ffffc9000300f920 EFLAGS: 00000246 RAX: 1ffffffff1778704 RBX: 0000000000000000 RCX: 52cca3877e381000 RDX: 0000000000000000 RSI: ffffffff8a59a860 RDI: ffffffff8a59a820 RBP: ffffc9000300fa58 R08: dffffc0000000000 R09: fffffbfff1ad334e R10: fffffbfff1ad334e R11: 1ffffffff1ad334d R12: ffffc9000300fd40 R13: dffffc0000000000 R14: ffffffff8bbc3820 R15: dffffc0000000000 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0xba/0x870 kernel/locking/lockdep.c:5634 _copy_from_user+0x29/0x170 lib/usercopy.c:14 copy_from_user include/linux/uaccess.h:192 [inline] __copy_msghdr_from_user net/socket.c:2318 [inline] copy_msghdr_from_user net/socket.c:2369 [inline] recvmsg_copy_msghdr net/socket.c:2621 [inline] ___sys_recvmsg+0x129/0x4f0 net/socket.c:2693 do_recvmmsg+0x344/0x7a0 net/socket.c:2791 __sys_recvmmsg net/socket.c:2870 [inline] __do_sys_recvmmsg net/socket.c:2893 [inline] __se_sys_recvmmsg net/socket.c:2886 [inline] __x64_sys_recvmmsg+0x18d/0x240 net/socket.c:2886 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f4f68fd0fc9 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:00007f4f67217038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f4f69228090 RCX: 00007f4f68fd0fc9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f4f69053f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4f69228128 R14: 00007f4f69228090 R15: 00007ffd5dfb9cc8 task:kworker/u4:13 state:R running task stack:22728 pid: 5800 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_notrace+0xca/0x110 kernel/sched/core.c:6650 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 rcu_is_watching+0x72/0xa0 kernel/rcu/tree.c:1124 rcu_read_lock include/linux/rcupdate.h:741 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:754 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline] batadv_iv_ogm_schedule+0x44d/0xe90 net/batman-adv/bat_iv_ogm.c:868 batadv_iv_send_outstanding_bat_ogm_packet+0x72d/0x840 net/batman-adv/bat_iv_ogm.c:1712 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread starved for 10485 jiffies! g45897 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:27464 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 4828 Comm: kworker/1:14 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events jump_label_update_timeout Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xb88/0xd70 kernel/smp.c:969 Code: b6 44 05 00 84 c0 0f 85 9d 00 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 66 49 0b 00 83 e3 01 75 07 e8 fc 45 0b 00 eb 43 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 11 41 f7 RSP: 0018:ffffc900034bf940 EFLAGS: 00000293 RAX: ffffffff816c84bb RBX: 0000000000000001 RCX: ffff888028890000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900034bfa80 R08: dffffc0000000000 R09: fffffbfff1ff7a19 R10: fffffbfff1ff7a19 R11: 1ffffffff1ff7a18 R12: ffff8880b9042848 R13: 1ffff11017208509 R14: ffff8880b913b3c0 R15: 0000000000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1442 [inline] text_poke_bp_batch+0x2a9/0x7c0 arch/x86/kernel/alternative.c:1642 text_poke_flush arch/x86/kernel/alternative.c:1833 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1840 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 __static_key_slow_dec_cpuslocked+0xf0/0x150 kernel/jump_label.c:248 __static_key_slow_dec kernel/jump_label.c:255 [inline] jump_label_update_timeout+0x1a/0x20 kernel/jump_label.c:263 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287