rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=1d94/1/0x4000000000000000 softirq=34640/34640 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5828/1:b..l rcu: (detected by 0, t=10506 jiffies, g=25101, q=105 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5989 Comm: kworker/u8:12 Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:135 [inline] RIP: 0010:cpumask_check include/linux/cpumask.h:142 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:587 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1143 [inline] RIP: 0010:trace_hrtimer_cancel include/trace/events/timer.h:317 [inline] RIP: 0010:debug_deactivate+0x3f/0x200 kernel/time/hrtimer.c:491 Code: d6 6c 8b e8 a3 0b 09 03 0f 1f 44 00 00 e8 69 65 11 00 65 8b 1d 56 96 c3 10 bf 07 00 00 00 89 de e8 96 69 11 00 83 fb 07 77 6d 4c 65 11 00 41 89 de c1 eb 06 48 8d 3c dd 70 a9 7d 8f be 08 00 RSP: 0018:ffffc90000a08d18 EFLAGS: 00000097 RAX: ffffffff81ae69ea RBX: 0000000000000001 RCX: 0000000000010000 RDX: ffff88806f0c9e00 RSI: 0000000000000001 RDI: 0000000000000007 RBP: ffffc90000a08e90 R08: ffffffff99aa8703 R09: 1ffffffff33550e0 R10: dffffc0000000000 R11: fffffbfff33550e1 R12: ffff88801a0a6340 R13: dffffc0000000000 R14: 1847db4cb8000000 R15: ffff8880b89278c0 FS: 0000000000000000(0000) GS:ffff888126200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc34f404f98 CR3: 000000005b270000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 6b e2 d3 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90004ccfa20 EFLAGS: 00000206 RAX: d9bdac9d5364df00 RBX: 0000000000000000 RCX: d9bdac9d5364df00 RDX: 0000000000000000 RSI: ffffffff8d921532 RDI: ffffffff8bc0ffa0 RBP: ffffffff8b1d0412 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8b1d0412 R12: 0000000000000002 R13: ffffffff8df3b860 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [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:3238 [inline] process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz-executor state:R running task stack:21400 pid:5828 tgid:5828 ppid:5810 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6971 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1194 [inline] copy_pmd_range+0x673c/0x7000 mm/memory.c:1255 copy_pud_range mm/memory.c:1292 [inline] copy_p4d_range mm/memory.c:1316 [inline] copy_page_range+0x95c/0xd40 mm/memory.c:1410 dup_mmap kernel/fork.c:726 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm+0x121c/0x2100 kernel/fork.c:1786 copy_process+0x16d3/0x3b80 kernel/fork.c:2429 kernel_clone+0x224/0x7f0 kernel/fork.c:2844 __do_sys_clone kernel/fork.c:2987 [inline] __se_sys_clone kernel/fork.c:2971 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2971 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc083f851d3 RSP: 002b:00007ffdfbb36f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc083f851d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555589c6d7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000005c832 R15: 00007ffdfbb37110 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g25101 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=24994 rcu: rcu_preempt kthread starved for 10506 jiffies! g25101 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27304 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245