rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4972/1:b..l rcu: (detected by 0, t=10502 jiffies, g=18593, q=2018157 ncpus=1) task:udevd state:R running task stack:24568 pid:4972 tgid:4972 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7284 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:7606 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa10 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__reset_page_owner+0x5f/0x190 mm/page_owner.c:329 Code: 89 c3 e8 c4 d5 80 ff 4c 8b 3d ed 74 77 0d 48 b8 00 00 00 00 00 fc ff df 49 01 df 49 8d 7f 08 48 89 fa 48 c1 ea 03 0f b6 04 02 <84> c0 74 08 3c 03 0f 8e 0e 01 00 00 48 89 df 45 8b 7f 08 0f b7 dd RSP: 0018:ffffc90002f6fb60 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: ffff888020d42da0 RCX: 0000000000000000 RDX: 1ffff110041a85b6 RSI: ffffffff828b748c RDI: ffff888020d42db0 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea0001d02480 R13: 0000002130db43b9 R14: 0000000000000000 R15: ffff888020d42da8 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010 alloc_filename fs/namei.c:147 [inline] do_getname+0x35/0x390 fs/namei.c:187 getname include/linux/fs.h:2557 [inline] getname_maybe_null include/linux/fs.h:2564 [inline] class_filename_maybe_null_constructor include/linux/fs.h:2588 [inline] vfs_fstatat+0xd0/0xe0 fs/stat.c:368 __do_sys_newfstatat+0x9d/0x120 fs/stat.c:538 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f58aab11b0a RSP: 002b:00007fff518656e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000561db573f420 RCX: 00007f58aab11b0a RDX: 00007fff518656f0 RSI: 0000561db572def3 RDI: 00000000ffffff9c RBP: 0000561deceb1668 R08: 00063478c1c69200 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fff518656f0 R14: 0000000000000000 R15: 00063478c1c69200 rcu: rcu_preempt kthread starved for 369 jiffies! g18593 f0x2 RCU_GP_WAIT_FQS(5) ->state=R ->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:27560 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7376 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x8f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x17a/0x220 kernel/rcu/tree.c:2330 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 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: 3227 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5947 Code: 05 cf 1a a6 13 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 de f0 5d 10 0f 82 c9 02 00 00 8b 35 7e 22 5e 10 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 6d 1a a6 13 0f 85 09 03 00 00 48 83 c4 RSP: 0018:ffffc90000006ca0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000200 RDX: 0000000000000101 RSI: ffffffff8e3bcc69 RDI: ffffffff8c625080 RBP: ffffffff8fdec5a0 R08: 000000007f1fed10 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000001 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888122947000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055557eb794e8 CR3: 000000006108b000 CR4: 00000000003526f0 Call Trace: 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+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:351 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:377 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010 dst_alloc+0x99/0x1a0 net/core/dst.c:90 rt_dst_alloc+0x35/0x3a0 net/ipv4/route.c:1683 __mkroute_output net/ipv4/route.c:2686 [inline] ip_route_output_key_hash_rcu+0x87a/0x2870 net/ipv4/route.c:2906 ip_route_output_key_hash+0x118/0x2b0 net/ipv4/route.c:2736 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x27/0x150 net/ipv4/route.c:2963 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x562/0x1260 net/ipv4/netfilter.c:54 synproxy_send_tcp.isra.0+0x341/0x6e0 net/netfilter/nf_synproxy_core.c:434 synproxy_send_client_synack+0x6ea/0x970 net/netfilter/nf_synproxy_core.c:487 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:59 [inline] nft_synproxy_do_eval+0xa6a/0xd30 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x2e5/0x19d0 net/netfilter/nf_tables_core.c:285 nft_do_chain_ipv4+0x1d0/0x250 net/netfilter/nft_chain_filter.c:24 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:280 NF_HOOK include/linux/netfilter.h:323 [inline] ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:481 [inline] ip_rcv_finish net/ipv4/ip_input.c:492 [inline] NF_HOOK include/linux/netfilter.h:325 [inline] NF_HOOK include/linux/netfilter.h:319 [inline] ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:612 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6297 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6410 process_backlog+0x487/0x1600 net/core/dev.c:6761 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7830 napi_poll net/core/dev.c:7893 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:8050 handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645 do_softirq kernel/softirq.c:546 [inline] do_softirq+0xaf/0xf0 kernel/softirq.c:533 __local_bh_enable_ip+0xff/0x120 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+0x25d/0xbd0 net/batman-adv/translation-table.c:3754 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] rescuer_thread+0x918/0x14e0 kernel/workqueue.c:3703 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245