rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4188/1:b..l P4612/1:b..l (detected by 1, t=10502 jiffies, g=8365, q=68) task:kworker/u4:9 state:R running task stack:27408 pid: 4612 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_mcast_mla_update Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681 RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc900044d7a78 EFLAGS: 00000206 RAX: e60e921c2ef08300 RBX: ffff8880268b3b80 RCX: e60e921c2ef08300 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff203a418 R10: dffffc0000000000 R11: fffffbfff203a419 R12: 0000000000000002 R13: 0000000000000246 R14: ffffffff8c31eaa0 R15: ffff8880268b46c0 __in6_dev_get include/net/addrconf.h:321 [inline] batadv_mcast_mla_rtr_flags_softif_get_ipv6 net/batman-adv/multicast.c:135 [inline] batadv_mcast_mla_rtr_flags_softif_get net/batman-adv/multicast.c:174 [inline] batadv_mcast_mla_rtr_flags_get net/batman-adv/multicast.c:232 [inline] batadv_mcast_mla_flags_get net/batman-adv/multicast.c:257 [inline] __batadv_mcast_mla_update net/batman-adv/multicast.c:876 [inline] batadv_mcast_mla_update+0x3b2/0x3150 net/batman-adv/multicast.c:915 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 task:syz-executor state:R running task stack:21432 pid: 4188 ppid: 4182 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681 RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc90002e3f7c0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ac588596eb6e3400 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740 RBP: ffffc90002e3f8d8 R08: dffffc0000000000 R09: 1ffffffff203a418 R10: dffffc0000000000 R11: fffffbfff203a419 R12: ffffffff8c31eaa0 R13: 1ffff920005c7f04 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:317 [inline] percpu_ref_put include/linux/percpu-refcount.h:338 [inline] obj_cgroup_put+0xe/0xc0 include/linux/memcontrol.h:816 memcg_slab_free_hook+0x6f/0x1f0 mm/slab.h:367 do_slab_free mm/slub.c:3437 [inline] ___cache_free+0x63/0x120 mm/slub.c:3511 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 kmem_cache_zalloc include/linux/slab.h:728 [inline] __alloc_file+0x25/0x240 fs/file_table.c:132 alloc_empty_file+0x90/0x180 fs/file_table.c:181 alloc_file+0x5b/0x4f0 fs/file_table.c:223 alloc_file_pseudo+0x180/0x200 fs/file_table.c:263 sock_alloc_file+0xb3/0x240 net/socket.c:464 sock_map_fd net/socket.c:488 [inline] __sys_socket+0x11d/0x170 net/socket.c:1597 __do_sys_socket net/socket.c:1602 [inline] __se_sys_socket net/socket.c:1600 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1600 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7efc222f6807 RSP: 002b:00007ffda8bcfdc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007efc222f6807 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 00007ffda8bd04cc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000011 R13: 00000000000927c0 R14: 0000000000013cda R15: 00007ffda8bd0520 rcu: rcu_preempt kthread starved for 10555 jiffies! g8365 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:27536 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 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: NMI backtrace for cpu 1 CPU: 1 PID: 4616 Comm: syz.2.87 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x843/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4ad/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:debug_smp_processor_id+0x0/0x10 lib/smp_processor_id.c:60 Code: 32 8a e8 43 01 00 00 65 c7 05 b8 2b 47 76 00 00 00 00 48 c7 c7 20 e8 32 8a e8 2c 01 00 00 65 ff 0d a1 2b 47 76 5b c3 00 00 cc <48> c7 c7 e0 f6 79 8a 48 c7 c6 20 f7 79 8a eb 00 55 41 57 41 56 53 RSP: 0018:ffffc900037e7ea0 EFLAGS: 00000282 RAX: 0000000000006701 RBX: 0000000000000000 RCX: 0000000080000000 RDX: 0000000000000002 RSI: ffffffff8a79f720 RDI: ffffffff8a79f6e0 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff203a418 R10: dffffc0000000000 R11: fffffbfff203a419 R12: dffffc0000000000 R13: ffff888061d05280 R14: ffff8880226ff020 R15: ffff8880226ff018 rcu_lockdep_current_cpu_online+0x35/0x130 kernel/rcu/tree.c:1171 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held+0x1a/0x40 kernel/rcu/update.c:309 __task_pid_nr_ns+0x1c4/0x420 kernel/pid.c:500 task_tgid_vnr include/linux/sched.h:1585 [inline] __ia32_sys_getpid+0x19/0x20 kernel/sys.c:945 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f47ec2bed97 Code: 8d 3d 08 8e 0b 00 e8 58 1d fa ff e8 23 87 00 00 0f 1f 00 b8 68 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007f47ea51eb08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: ffffffffffffffda RBX: 00007f47ea51ec70 RCX: 00007f47ec2bed97 RDX: 00007f47ea51eb40 RSI: 00007f47ea51ec70 RDI: 0000000000000021 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007f47ec53f038 R14: 00007ffc2e4cab10 R15: 00007ffc2e4cabf8 sched: RT throttling activated