rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (2 ticks this GP) idle=24c4/1/0x4000000000000000 softirq=18343/18343 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=13053, q=730 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 1166 Comm: kworker/u8:8 Not tainted 6.16.0-rc7-syzkaller-00100-gafd8c2c9e2e2 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:lock_release+0x0/0x3e0 kernel/locking/lockdep.c:5879 Code: de e8 64 8e 57 03 48 8b 3c 24 e9 08 fa ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 30 49 89 f5 49 RSP: 0018:ffffc90000007bd8 EFLAGS: 00000086 RAX: f3f3f300f1f1f1f1 RBX: 0000000000000802 RCX: 0000000000000001 RDX: 0000000000000001 RSI: ffffffff84c69512 RDI: ffffffff99cea548 RBP: ffffc90000007c78 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f6c R12: dffffc0000000000 R13: ffff88807160a690 R14: ffffffff99cea530 R15: 1ffff92000000f7c FS: 0000000000000000(0000) GS:ffff888125c23000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fde9ee6b286 CR3: 0000000074d66000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194 debug_object_activate+0x2e2/0x420 lib/debugobjects.c:836 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_lock_acquire include/linux/rcupdate.h:331 [inline] RIP: 0010:rcu_read_lock include/linux/rcupdate.h:841 [inline] RIP: 0010:batadv_nc_process_nc_paths+0xd5/0x3a0 net/batman-adv/network-coding.c:687 Code: 48 03 28 e8 0d 01 6c f6 48 8d 05 00 00 00 00 48 c7 c7 e0 f0 13 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 48 89 44 24 28 <50> e8 05 5a 62 f6 48 83 c4 08 e8 9c cf 31 00 41 89 c6 31 ff 89 c6 RSP: 0018:ffffc900040079b0 EFLAGS: 00000246 RAX: ffffffff8b3be01a RBX: ffffffff8b3be310 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e13f0e0 RBP: ffff8880283da950 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1f43bdf R12: dffffc0000000000 R13: 1ffff1100f6c8b13 R14: 000000000000002a R15: ffff88807b644d80 batadv_nc_worker+0x429/0x610 net/batman-adv/network-coding.c:728 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13053 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4257 rcu: rcu_preempt kthread starved for 10502 jiffies! g13053 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26056 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16fd/0x4cf0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0x165/0x360 kernel/sched/core.c:6879 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245