rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4339/1:b..l (detected by 0, t=10502 jiffies, g=10241, q=175) task:kworker/u4:9 state:R running task stack:23776 pid: 4339 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_irq+0xb1/0x150 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216 Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 74 a4 8a 7e 65 8b RSP: 0018:ffffc9000457fa38 EFLAGS: 00000293 RAX: ffffffff8979c436 RBX: ffff888061d04e70 RCX: ffff88807be75940 RDX: 0000000000000000 RSI: ffffffff8a59a220 RDI: ffffffff8a59a1e0 RBP: ffffc9000457fb80 R08: dffffc0000000000 R09: fffffbfff1ff7619 R10: fffffbfff1ff7619 R11: 1ffffffff1ff7618 R12: ffff888022fe74c0 R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000 rcu_read_lock include/linux/rcupdate.h:740 [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+0x456/0xe90 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 10523 jiffies! g10241 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:27200 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4905 Comm: syz.3.130 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0xc/0x12 Code: 56 57 41 50 41 51 41 52 41 53 e8 2f 08 00 00 41 5b 41 5a 41 59 41 58 5f 5e 5a 59 c3 90 90 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <3c> 01 75 02 5a c3 56 0f b6 f0 e8 c5 ff ff ff 5e 5a c3 66 90 55 48 RSP: 0018:ffffc90004807b08 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff88807a552e40 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88807a552e40 RBP: 1ffff1100f4aa5c9 R08: dffffc0000000000 R09: ffffed100f4aa5c9 R10: ffffed100f4aa5c9 R11: 1ffff1100f4aa5c8 R12: dffffc0000000000 R13: 1ffff1100f4aa5ca R14: ffff88807a552e50 R15: ffff88807a552e48 FS: 00007f5ae5e016c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 0000000022f21000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:590 [inline] queued_spin_unlock arch/x86/include/asm/qspinlock.h:56 [inline] do_raw_spin_unlock+0x11d/0x230 kernel/locking/spinlock_debug.c:141 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_irq+0x1a/0x40 kernel/locking/spinlock.c:202 set_current_blocked kernel/signal.c:3072 [inline] signal_delivered kernel/signal.c:2936 [inline] signal_setup_done+0x28c/0x440 kernel/signal.c:2947 handle_signal arch/x86/kernel/signal.c:842 [inline] arch_do_signal_or_restart+0xf2e/0x1300 arch/x86/kernel/signal.c:869 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f5ae7bc22e0 Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 8a 3e 08 00 e8 25 90 f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48 RSP: 002b:00007f5ae5e00b38 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f5ae7de0fa8 RCX: 00007f5ae7b99ba9 RDX: 00007f5ae5e00b40 RSI: 00007f5ae5e00c70 RDI: 0000000000000021 RBP: 00007f5ae7de0fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5ae7de1038 R14: 00007ffca26afb20 R15: 00007ffca26afc08