rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4379/1:b..l
	(detected by 0, t=10502 jiffies, g=3441, q=186 ncpus=2)
task:kworker/u4:5    state:R  running task     stack:0     pid:4379  ppid:2      flags:0x00000008
Workqueue: bat_events batadv_nc_worker
Call trace:
 __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562
 preempt_schedule_irq+0x8c/0x1ac kernel/sched/core.c:6874
 arm64_preempt_schedule_irq+0x44/0x54 arch/arm64/kernel/entry-common.c:265
 __el1_irq arch/arm64/kernel/entry-common.c:474 [inline]
 el1_interrupt+0x3c/0x54 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
 lock_acquire+0x24c/0x63c kernel/locking/lockdep.c:5665
 rcu_lock_acquire+0x40/0x4c include/linux/rcupdate.h:350
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xc0/0x554 net/batman-adv/network-coding.c:719
 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292
 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
rcu: rcu_preempt kthread starved for 10502 jiffies! g3441 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:0     pid:16    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562
 preempt_schedule_common+0xec/0x1a0 kernel/sched/core.c:6731
 preempt_schedule+0x64/0x84 kernel/sched/core.c:6755
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0xa8/0xac kernel/locking/spinlock.c:194
 debug_object_free+0x2a8/0x450 lib/debugobjects.c:855
 destroy_timer_on_stack kernel/time/timer.c:812 [inline]
 schedule_timeout+0x1b0/0x2f4 kernel/time/timer.c:2172
 rcu_gp_fqs_loop+0x2b4/0x1378 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xb4/0x2fc kernel/rcu/tree.c:1905
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 4818 Comm: syz.3.87 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : should_resched arch/arm64/include/asm/preempt.h:79 [inline]
pc : __local_bh_enable_ip+0x200/0x37c kernel/softirq.c:428
lr : __local_bh_enable_ip+0x1f8/0x37c kernel/softirq.c:426
sp : ffff800021967b00
x29: ffff800021967b10 x28: ffff70000432cfa4 x27: 0000000000000001
x26: dfff800000000000 x25: ffff0000deeb0000 x24: 0000000000000001
x23: dfff800000000000 x22: 1fffe0001bdd6001 x21: ffff800008030954
x20: ffff00019f556980 x19: ffff0000deeb0008 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000082d91a4 x15: 0000000000000002
x14: 0000000000000002 x13: 0000000000ff0100 x12: 0000000000080000
x11: 000000000007ffff x10: ffff8000265a6000 x9 : ffff80000a8db9f0
x8 : 00000000000000e0 x7 : 0000000018000004 x6 : 0000ffff80f9ab00
x5 : ffff800021967d70 x4 : ffff0000d9b757f8 x3 : 0000000000000000
x2 : ffff800021967a40 x1 : ffff800011b8da80 x0 : ffff80018a3de000
Call trace:
 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:35 [inline]
 __local_bh_enable_ip+0x200/0x37c kernel/softirq.c:426
 local_bh_enable+0x28/0x34 include/linux/bottom_half.h:33
 put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:276 [inline]
 fpsimd_preserve_current_state+0xa8/0x164 arch/arm64/kernel/fpsimd.c:1663
 fpsimd_signal_preserve_current_state+0x2c/0x1bc arch/arm64/kernel/fpsimd.c:1673
 setup_rt_frame arch/arm64/kernel/signal.c:983 [inline]
 handle_signal arch/arm64/kernel/signal.c:1035 [inline]
 do_signal arch/arm64/kernel/signal.c:1110 [inline]
 do_notify_resume+0x708/0x2aa4 arch/arm64/kernel/signal.c:1148
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585