rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5811/1:b..l P5513/1:b..l rcu: (detected by 0, t=10502 jiffies, g=33685, q=1162134 ncpus=2) task:crond state:R running task stack:24232 pid:5513 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 unwind_next_frame+0x200f/0x2970 arch/x86/kernel/unwind_orc.c:672 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1181 [inline] free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458 discard_slab mm/slub.c:2127 [inline] __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667 put_cpu_partial+0x17c/0x250 mm/slub.c:2743 __slab_free+0x319/0x400 mm/slub.c:3700 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519 kmem_cache_zalloc include/linux/slab.h:711 [inline] lsm_file_alloc security/security.c:613 [inline] security_file_alloc+0x34/0x120 security/security.c:2604 init_file+0x94/0x1f0 fs/file_table.c:161 alloc_empty_file+0xb7/0x1d0 fs/file_table.c:210 path_openat+0x113/0x3230 fs/namei.c:3783 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fca353f9c3a RSP: 002b:00007fffdcc764c8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000555f22a782a0 RCX: 00007fca353f9c3a RDX: 0000000000080000 RSI: 00007fca3549645a RDI: 00000000ffffff9c RBP: 0000000000000008 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 00007fca354947f4 R13: 00007fca354947f4 R14: 0000000000000001 R15: 0000000000000034 task:kworker/1:4 state:R running task stack:23152 pid:5811 ppid:2 flags:0x00004000 Workqueue: events_power_efficient gc_worker Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:seqcount_lockdep_reader_access+0x19a/0x1d0 include/linux/seqlock.h:105 Code: f8 4d 85 e4 75 16 e8 a5 00 ca f8 eb 15 e8 9e 00 ca f8 e8 f9 c3 c9 01 4d 85 e4 74 ea e8 8f 00 ca f8 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc9000471f9a0 EFLAGS: 00000293 RAX: ffffffff88bd2711 RBX: 0000000000000000 RCX: ffff888079f81e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000471fa50 R08: ffffffff911c7597 R09: 1ffffffff2238eb2 R10: dffffc0000000000 R11: fffffbfff2238eb3 R12: 0000000000000200 R13: dffffc0000000000 R14: 1ffff920008e3f34 R15: dffffc0000000000 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:350 [inline] gc_worker+0x317/0x1490 net/netfilter/nf_conntrack_core.c:1504 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: rcu_preempt kthread starved for 502 jiffies! g33685 f0x2 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:27656 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3382 Comm: kworker/R-bat_e Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: bat_events batadv_dat_purge RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215 Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 7c 0a 04 0d 48 89 de 5b e9 f3 6b 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 10 8e 7c 7e 65 8b 15 11 8e 7c 7e 81 e2 00 01 ff 00 74 RSP: 0018:ffffc900001ef840 EFLAGS: 00000297 RAX: ffffffff812f4286 RBX: 0000000000000002 RCX: 0000000000000100 RDX: ffff88802dab3c00 RSI: 0000000000000002 RDI: 0000000000000040 RBP: 0000000000000000 R08: ffffc900001ef900 R09: 0000000000000000 R10: ffffc900001ef8e8 R11: fffff5200003df29 R12: 0000000000000002 R13: 0000000000000000 R14: ffffc900001ef908 R15: ffff88802dab3c00 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f29ecc00020 CR3: 000000002d78e000 CR4: 00000000003506e0 Call Trace: get_stack_info+0xf6/0x170 arch/x86/kernel/dumpstack_64.c:213 __unwind_start+0x48b/0x7e0 arch/x86/kernel/unwind_orc.c:729 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] ref_tracker_alloc+0x162/0x4c0 lib/ref_tracker.c:203 __netdev_tracker_alloc include/linux/netdevice.h:4110 [inline] netdev_hold include/linux/netdevice.h:4139 [inline] dst_init+0xd9/0x480 net/core/dst.c:52 dst_alloc+0x12e/0x170 net/core/dst.c:94 rt_dst_alloc net/ipv4/route.c:1662 [inline] __mkroute_output net/ipv4/route.c:2626 [inline] ip_route_output_key_hash_rcu+0x14f6/0x2370 net/ipv4/route.c:2848 ip_route_output_key_hash+0x1f3/0x330 net/ipv4/route.c:2677 __ip_route_output_key include/net/route.h:134 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2905 ip_route_output_key include/net/route.h:150 [inline] ip_route_me_harder+0x6bc/0xe80 net/ipv4/netfilter.c:52 synproxy_send_tcp+0x2fb/0x600 net/netfilter/nf_synproxy_core.c:431 synproxy_send_client_synack+0x890/0xde0 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x34b/0x4e0 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x306/0x570 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x44e/0x1600 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x29b/0x380 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline] nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:259 [inline] NF_HOOK+0x21d/0x3b0 include/linux/netfilter.h:302 NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304 __netif_receive_skb_one_core net/core/dev.c:5646 [inline] __netif_receive_skb+0xcc/0x290 net/core/dev.c:5760 process_backlog+0x391/0x6f0 net/core/dev.c:6088 __napi_poll+0xc0/0x460 net/core/dev.c:6650 napi_poll net/core/dev.c:6717 [inline] net_rx_action+0x616/0xc40 net/core/dev.c:6853 handle_softirqs+0x280/0x820 kernel/softirq.c:578 do_softirq+0xfa/0x1a0 kernel/softirq.c:479 __local_bh_enable_ip+0x184/0x1c0 kernel/softirq.c:406 spin_unlock_bh include/linux/spinlock.h:396 [inline] __batadv_dat_purge net/batman-adv/distributed-arp-table.c:186 [inline] batadv_dat_purge+0x2da/0x3c0 net/batman-adv/distributed-arp-table.c:205 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 rescuer_thread+0x74e/0x10d0 kernel/workqueue.c:2927 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293