rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10660/1:b..l P7807/2:b..l rcu: (detected by 0, t=10502 jiffies, g=57421, q=306 ncpus=2) task:kworker/u8:43 state:R running task stack:21288 pid:7807 tgid:7807 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5030 kernel/sched/core.c:6864 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:109 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x2b4/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 00 00 fc ff df 0f 84 03 02 00 00 4a 8d 14 ad f4 b0 8b 8f 45 29 e8 4a 8d 1c 82 48 83 c3 fc 49 89 d5 48 39 da 0f 86 1c 10 00 00 <49> 29 d5 e9 80 00 00 00 31 db e9 eb 16 00 00 49 81 fc 00 90 e1 90 RSP: 0018:ffffc90003217258 EFLAGS: 00000202 RAX: ffffffff8ffe5260 RBX: ffffffff8ffe5264 RCX: ffffffff8ffe5268 RDX: ffffffff8ffe5264 RSI: ffffffff90afc784 RDI: ffffffff8bbf8180 RBP: ffffffff8ffe5268 R08: 0000000000000001 R09: ffffffff81745035 R10: ffffc90003217378 R11: ffffffff81adcc20 R12: ffffffff8b24b59e R13: ffffffff8ffe5264 R14: ffffc90003217328 R15: ffffffff8ffe5264 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] batadv_forw_packet_alloc+0x1e9/0x390 net/batman-adv/send.c:506 batadv_iv_ogm_aggregate_new net/batman-adv/bat_iv_ogm.c:570 [inline] batadv_iv_ogm_queue_add+0x85f/0xd30 net/batman-adv/bat_iv_ogm.c:677 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:854 [inline] batadv_iv_ogm_schedule+0xb48/0xf00 net/batman-adv/bat_iv_ogm.c:873 batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1709 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261 process_scheduled_works kernel/workqueue.c:3344 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 task:udevd state:R running task stack:23592 pid:10660 tgid:10660 ppid:5202 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5030 kernel/sched/core.c:6864 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0xb0/0x350 kernel/locking/lockdep.c:5844 Code: 75 85 df 0d 00 0f 84 fa 00 00 00 65 8b 05 78 0f d8 10 85 c0 0f 85 eb 00 00 00 65 48 8b 04 25 08 60 76 92 83 b8 2c 0b 00 00 00 <0f> 85 d5 00 00 00 48 c7 44 24 30 00 00 00 00 9c 8f 44 24 30 4c 89 RSP: 0018:ffffc9000e0378b8 EFLAGS: 00000246 RAX: ffff888057df1e80 RBX: 0000000000000000 RCX: 8ed3a700a485e800 RDX: 0000000000000000 RSI: ffffffff81745052 RDI: 1ffffffff1be7b30 RBP: ffffffff81745035 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc9000e037a78 R11: ffffffff81adcc20 R12: 0000000000000002 R13: ffffffff8df3d980 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2501 [inline] slab_free mm/slub.c:6663 [inline] kmem_cache_free+0x48f/0x640 mm/slub.c:6774 fput_close_sync+0x113/0x220 fs/file_table.c:573 __do_sys_close fs/open.c:1584 [inline] __se_sys_close fs/open.c:1569 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1569 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcefd2a7407 RSP: 002b:00007ffdb7c5b810 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007fcefd94d880 RCX: 00007fcefd2a7407 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009 RBP: 00007fcefd94d6e8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000009 rcu: rcu_preempt kthread starved for 10482 jiffies! g57421 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:26968 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5030 kernel/sched/core.c:6864 __schedule_loop kernel/sched/core.c:6946 [inline] schedule+0x165/0x360 kernel/sched/core.c:6961 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 70 0c 00 f3 0f 1e fa fb f4 c8 f2 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: 5b49e887cee4ff00 RBX: ffffffff8197acb7 RCX: 5b49e887cee4ff00 RDX: 0000000000000001 RSI: ffffffff8d78f71d RDI: ffffffff8bbf81e0 RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f7deb70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a60 FS: 0000000000000000(0000) GS:ffff888125eba000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000021b2 CR3: 000000000dd38000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3a7/0x410 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147