rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P59/1:b..l rcu: (detected by 0, t=10502 jiffies, g=12289, q=525 ncpus=2) task:kworker/u4:4 state:R running task stack:24304 pid:59 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:lockdep_enabled kernel/locking/lockdep.c:122 [inline] RIP: 0010:lock_acquire+0x12a/0x410 kernel/locking/lockdep.c:5730 Code: c0 0f 85 2e 01 00 00 65 4c 8b 35 b1 ab 9c 7e 49 81 c6 dc 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 f3 01 00 00 <41> 83 3e 00 0f 85 01 01 00 00 48 c7 84 24 a0 00 00 00 00 00 00 00 RSP: 0018:ffffc900015b7a40 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 82888291fcadd200 RDX: 0000000000000000 RSI: ffffffff8afc6f20 RDI: ffffffff8afc6ee0 RBP: ffffc900015b7b48 R08: ffffffff8e4a8e2f R09: 1ffffffff1c951c5 R10: dffffc0000000000 R11: fffffbfff1c951c6 R12: 1ffff920002b6f54 R13: ffffffff8cd2fee0 R14: ffff88801ce6c6dc 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 10528 jiffies! g12289 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:26728 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: 0 PID: 6043 Comm: syz.2.30 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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 4a a2 ee f6 48 89 df e8 62 74 ef f6 e8 fd 1a 13 f7 fb bf 01 00 00 00 32 96 e2 f6 65 8b 05 23 cd 8a 75 85 c0 74 02 5b c3 e8 00 b3 87 RSP: 0018:ffffc90003607c78 EFLAGS: 00000286 RAX: a719ba203cfcf800 RBX: ffff88802d2c3780 RCX: a719ba203cfcf800 RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001 RBP: ffff88802d2c3c18 R08: ffffffff8e4a8e2f R09: 1ffffffff1c951c5 R10: dffffc0000000000 R11: fffffbfff1c951c6 R12: 1ffff11005a58783 R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007fbe167fe6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 000000002c29c000 CR4: 00000000003506f0 Call Trace: spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x11f5/0x1400 kernel/signal.c:2905 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 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: 0033:0x7fbe1718f749 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:00007fbe167fe038 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007fbe173e5fa0 RCX: 00007fbe1718f749 RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fbe17213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbe173e6038 R14: 00007fbe173e5fa0 R15: 00007ffc358f21b8