rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5582/1:b..l rcu: (detected by 0, t=10502 jiffies, g=86945, q=516 ncpus=1) task:syz-executor state:R running task stack:22560 pid:5582 tgid:5582 ppid:5580 task_flags:0x400100 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 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:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline] RIP: 0010:lock_acquire kernel/locking/lockdep.c:5864 [inline] RIP: 0010:lock_acquire+0x166/0x370 kernel/locking/lockdep.c:5825 Code: bd 00 00 00 65 8b 05 89 df 9e 12 85 c0 0f 85 ae 00 00 00 65 48 8b 05 c1 98 9e 12 8b 90 a4 0b 00 00 85 d2 0f 85 98 00 00 00 9c <8f> 04 24 fa 48 c7 c7 92 dc 49 8e e8 6a 44 d8 09 45 89 e8 44 89 e1 RSP: 0018:ffffc90003967868 EFLAGS: 00000246 RAX: ffff88807e342580 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff81b873d1 RDI: fffffbfff1dbd060 RBP: ffffffff8ede8300 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000200 R11: 000000000000b896 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x3cd/0x7e0 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950 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_kmalloc+0x8a/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x322/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] alloc_pipe_info+0x1ec/0x590 fs/pipe.c:900 get_pipe_inode fs/pipe.c:977 [inline] create_pipe_files+0x8c/0x970 fs/pipe.c:1009 __do_pipe_flags fs/pipe.c:1071 [inline] do_pipe2+0xbd/0x1e0 fs/pipe.c:1119 __do_sys_pipe2 fs/pipe.c:1137 [inline] __se_sys_pipe2 fs/pipe.c:1135 [inline] __x64_sys_pipe2+0x54/0x80 fs/pipe.c:1135 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f103d59d109 RSP: 002b:00007fffcf88c318 EFLAGS: 00000246 ORIG_RAX: 0000000000000125 RAX: ffffffffffffffda RBX: 000055555ab74400 RCX: 00007f103d59d109 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 00007fffcf88c328 RBP: 00007fffcf88c900 R08: 00007f103d7f2e20 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffcf88c740 R13: 000055555ab703d8 R14: 000055555ab743b0 R15: 00007fffcf88c480 rcu: rcu_preempt kthread starved for 328 jiffies! g86945 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:28984 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 3214 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(lazy) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x36/0x90 kernel/kcov.c:246 Code: f1 49 89 d2 65 48 8b 3d f0 31 7a 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc cc cc 8b 87 2c 17 00 00 <85> c0 74 f1 8b 87 00 17 00 00 83 f8 03 75 e6 48 8b 87 08 17 00 00 RSP: 0018:ffffc90000007268 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000001000011 RCX: ffffffff84dc0857 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888034130000 RBP: 1ffff92000000e4f R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000000759b R12: 0000000000000000 R13: 0000000000000000 R14: ffff88804f18e428 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888123bd6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555731014e8 CR3: 000000000eb94000 CR4: 00000000003526f0 Call Trace: netlbl_secattr_destroy include/net/netlabel.h:368 [inline] selinux_netlbl_skbuff_setsid+0x327/0x5e0 security/selinux/netlabel.c:263 selinux_ip_output+0x1f1/0x2a0 security/selinux/hooks.c:6071 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] __ip_local_out+0x541/0xb80 net/ipv4/ip_output.c:120 ip_local_out+0x2a/0x1f0 net/ipv4/ip_output.c:129 synproxy_send_tcp.isra.0+0x481/0x680 net/netfilter/nf_synproxy_core.c:442 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+0xa1c/0xce0 net/netfilter/nft_synproxy.c:141 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_inet+0xf3/0x400 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:480 [inline] ip_rcv_finish net/ipv4/ip_input.c:492 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:612 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6216 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6329 process_backlog+0x37a/0x1580 net/core/dev.c:6680 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7739 napi_poll net/core/dev.c:7802 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:7959 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xac/0xe0 kernel/softirq.c:510 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_local_purge+0x21c/0x3d0 net/batman-adv/translation-table.c:1366 batadv_tt_purge+0x8b/0xbd0 net/batman-adv/translation-table.c:3565 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] rescuer_thread+0x905/0x14a0 kernel/workqueue.c:3629 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245