rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16508/1:b..l rcu: (detected by 1, t=10503 jiffies, g=66025, q=1213 ncpus=2) task:syz.4.2715 state:R running task stack:25424 pid:16508 tgid:16506 ppid:5612 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17d4/0x5820 kernel/sched/core.c:7270 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7592 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913 Code: ff ff ff e8 40 1c 40 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 92 f7 f0 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 07 24 da RSP: 0018:ffffc900057df1a0 EFLAGS: 00000296 RAX: 41590c9ad3baf100 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000105209fd RSI: ffffffff8e6fb3b4 RDI: ffffffff8c6d8b80 RBP: ffff888054725dc0 R08: 0a00000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: ffffffff8ed5c6e0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 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 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6499 [inline] kfree+0x1c5/0x650 mm/slub.c:6792 free_func_state kernel/bpf/verifier.c:1598 [inline] bpf_free_verifier_state+0xdc/0x270 kernel/bpf/verifier.c:1615 free_states kernel/bpf/verifier.c:19237 [inline] do_check_common+0x4dab/0x5d30 kernel/bpf/verifier.c:19419 do_check_main kernel/bpf/verifier.c:19507 [inline] bpf_check+0x2639/0x2e10 kernel/bpf/verifier.c:21162 bpf_prog_load+0x14d6/0x1c20 kernel/bpf/syscall.c:3133 __sys_bpf+0xd0d/0xd90 kernel/bpf/syscall.c:6367 __do_sys_bpf kernel/bpf/syscall.c:6486 [inline] __se_sys_bpf kernel/bpf/syscall.c:6483 [inline] __x64_sys_bpf+0xba/0xd0 kernel/bpf/syscall.c:6483 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f900d39e159 RSP: 002b:00007f900e249028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f900d626090 RCX: 00007f900d39e159 RDX: 0000000000000094 RSI: 0000200000000040 RDI: 0000000000000005 RBP: 00007f900d435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f900d626128 R14: 00007f900d626090 R15: 00007ffd9b3f54c8 rcu: rcu_preempt kthread starved for 4723 jiffies! g66025 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27752 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17d4/0x5820 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 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: 1 UID: 0 PID: 8689 Comm: kworker/u8:25 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:lock_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5987 Code: 1a 00 00 b8 ff ff ff ff 65 0f c1 05 dc 1c b1 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 db ff 02 00 cc 90 0f 0b 90 48 c7 RSP: 0018:ffffc90000a176a0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 8000000000000101 RDX: 8000000000000100 RSI: ffffffff8e6fb3b4 RDI: ffffffff8c6d8b80 RBP: 00000000ffffffff R08: 0000000000000100 R09: ffffc90000a17a10 R10: ffffc90000a17860 R11: fffff52000142f0e R12: 0000000000000246 R13: ffff8880296c3e80 R14: ffffffff8ed5c6e0 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff888124ddf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcb8568a6b0 CR3: 000000000eb48000 CR4: 00000000003526f0 Call Trace: __in6_dev_get include/net/addrconf.h:348 [inline] ip6_ignore_linkdown+0x66/0x140 include/net/addrconf.h:457 find_match+0x9c/0xb40 net/ipv6/route.c:783 __find_rr_leaf+0x243/0x740 net/ipv6/route.c:872 find_rr_leaf net/ipv6/route.c:893 [inline] rt6_select net/ipv6/route.c:937 [inline] fib6_table_lookup+0x3c6/0xae0 net/ipv6/route.c:2255 ip6_pol_route+0x229/0x14d0 net/ipv6/route.c:2292 pol_lookup_func include/net/ip6_fib.h:672 [inline] __fib6_rule_action net/ipv6/fib6_rules.c:240 [inline] fib6_rule_action+0x9d7/0xc00 net/ipv6/fib6_rules.c:278 fib_rules_lookup+0x770/0xeb0 net/core/fib_rules.c:338 fib6_rule_lookup+0x1a0/0x730 net/ipv6/fib6_rules.c:115 ip6_route_input_lookup net/ipv6/route.c:2363 [inline] ip6_route_input+0x78d/0xb20 net/ipv6/route.c:2666 ip6_rcv_finish+0x141/0x280 net/ipv6/ip6_input.c:117 ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:988 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 __netif_receive_skb_one_core net/core/dev.c:6264 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] netif_receive_skb_internal net/core/dev.c:6463 [inline] netif_receive_skb+0x278/0xbf0 net/core/dev.c:6522 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:325 br_handle_frame_finish+0x1136/0x1950 net/bridge/br_input.c:-1 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30c0 net/core/dev.c:6151 __netif_receive_skb_one_core net/core/dev.c:6262 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] process_backlog+0x727/0x18b0 net/core/dev.c:6728 __napi_poll+0xaa/0x330 net/core/dev.c:7787 napi_poll net/core/dev.c:7850 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8007 handle_softirqs+0x226/0x860 kernel/softirq.c:645 do_softirq+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 spin_unlock_bh include/linux/spinlock.h:407 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2390 [inline] batadv_tt_purge+0x4ae/0xa10 net/batman-adv/translation-table.c:3754 process_one_work kernel/workqueue.c:3387 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551 kthread+0x38b/0x480 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