rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15464/1:b..l rcu: (detected by 0, t=10506 jiffies, g=85857, q=68 ncpus=2) task:syz.9.2582 state:R running task stack:24600 pid:15464 tgid:15458 ppid:11910 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457 local_bh_enable include/linux/bottom_half.h:33 [inline] xdp_test_run_batch net/bpf/test_run.c:356 [inline] bpf_test_run_xdp_live+0x1976/0x1c20 net/bpf/test_run.c:378 bpf_prog_test_run_xdp+0x7d8/0x11d0 net/bpf/test_run.c:1463 bpf_prog_test_run+0x2c5/0x340 kernel/bpf/syscall.c:4794 __sys_bpf+0xa22/0xd90 kernel/bpf/syscall.c:6376 __do_sys_bpf kernel/bpf/syscall.c:6477 [inline] __se_sys_bpf kernel/bpf/syscall.c:6474 [inline] __x64_sys_bpf+0xba/0xd0 kernel/bpf/syscall.c:6474 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbe2cf9e019 RSP: 002b:00007fbe2deea028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fbe2d225fa0 RCX: 00007fbe2cf9e019 RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007fbe2d03500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbe2d226038 R14: 00007fbe2d225fa0 R15: 00007ffdfdb97568 rcu: rcu_preempt kthread timer wakeup didn't happen for 10476 jiffies! g85857 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=41226 rcu: rcu_preempt kthread starved for 10477 jiffies! g85857 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:27416 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 43 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:rcu_rdp_cpu_online kernel/rcu/tree.c:4036 [inline] RIP: 0010:rcu_lockdep_current_cpu_online+0x8e/0x120 kernel/rcu/tree.c:4077 Code: df e8 f6 c8 88 00 48 8b 03 48 8d 98 80 e1 6e 93 48 8d b8 a8 e1 6e 93 48 89 f8 48 c1 e8 03 42 80 3c 30 00 74 05 e8 d2 c8 88 00 <4c> 8b 7b 28 48 83 c3 20 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 RSP: 0018:ffffc90000b36df8 EFLAGS: 00000246 RAX: 1ffff110170c7835 RBX: ffff8880b863c180 RCX: 0000000000000203 RDX: ffff88801ee99f00 RSI: ffffffff8c4c1c60 RDI: ffff8880b863c1a8 RBP: ffffc90000b36ee8 R08: ffffffff81ead6e9 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c20 R12: ffff8880280c6f48 R13: ffff8880280c6788 R14: dffffc0000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888124f4e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d422ff8 CR3: 0000000025edc000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:113 [inline] rcu_read_lock_any_held+0x1e/0x90 kernel/rcu/update.c:384 __rhashtable_lookup include/linux/rhashtable.h:633 [inline] rhashtable_lookup_likely include/linux/rhashtable.h:684 [inline] rhtab_lookup_elem+0x3a7/0xd90 kernel/bpf/hashtab.c:2916 rhtab_map_delete_elem+0xc6/0x190 kernel/bpf/hashtab.c:2981 bpf_prog_a4f1e23443ac9f8e+0x4e/0x56 bpf_dispatcher_nop_func include/linux/bpf.h:1453 [inline] __bpf_prog_run include/linux/filter.h:724 [inline] bpf_prog_run include/linux/filter.h:731 [inline] bpf_prog_run_array include/linux/bpf.h:2605 [inline] trace_call_bpf+0x3f0/0xb80 kernel/trace/bpf_trace.c:147 perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:11398 do_perf_trace_lock include/trace/events/lock.h:49 [inline] perf_trace_lock+0x32d/0x410 include/trace/events/lock.h:49 __do_trace_lock_release include/trace/events/lock.h:68 [inline] trace_lock_release include/trace/events/lock.h:68 [inline] lock_release+0x38e/0x3c0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x375/0x720 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] batadv_tvlv_container_register+0x3f/0x790 net/batman-adv/tvlv.c:244 batadv_tt_tvlv_container_update+0x584/0x660 net/batman-adv/translation-table.c:1069 batadv_tt_local_commit_changes_nolock+0xca3/0xdb0 net/batman-adv/translation-table.c:-1 batadv_tt_local_commit_changes+0x26/0x40 net/batman-adv/translation-table.c:3723 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:844 [inline] batadv_iv_ogm_schedule+0x2a2/0xff0 net/batman-adv/bat_iv_ogm.c:918 batadv_iv_send_outstanding_bat_ogm_packet+0x67a/0x790 net/batman-adv/bat_iv_ogm.c:1807 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245