IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4194/1:b..l (detected by 0, t=10502 jiffies, g=49409, q=72) task:syz-executor state:R running task stack:21984 pid: 4194 ppid: 4177 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202 spin_unlock_irq include/linux/spinlock.h:414 [inline] loop_queue_work drivers/block/loop.c:1069 [inline] loop_queue_rq+0x9e0/0xac0 drivers/block/loop.c:2202 __blk_mq_issue_directly block/blk-mq.c:2014 [inline] __blk_mq_try_issue_directly+0x497/0x810 block/blk-mq.c:2070 blk_mq_request_issue_directly block/blk-mq.c:2118 [inline] blk_mq_try_issue_list_directly+0x1a1/0x530 block/blk-mq.c:2136 blk_mq_sched_insert_requests+0x2d6/0x5c0 block/blk-mq-sched.c:512 blk_mq_flush_plug_list+0x57f/0x660 block/blk-mq.c:1971 blk_flush_plug_list+0x3ec/0x430 block/blk-core.c:1734 blk_finish_plug+0x59/0x80 block/blk-core.c:1751 btrfs_write_and_wait_transaction fs/btrfs/transaction.c:1214 [inline] btrfs_commit_transaction+0x1ca8/0x3440 fs/btrfs/transaction.c:2445 close_ctree+0x3d5/0x8c0 fs/btrfs/disk-io.c:4470 generic_shutdown_super+0x130/0x300 fs/super.c:475 kill_anon_super+0x36/0x70 fs/super.c:1089 btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2390 deactivate_locked_super+0x93/0xf0 fs/super.c:335 cleanup_mnt+0x418/0x4d0 fs/namespace.c:1148 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f94360c39f7 RSP: 002b:00007ffe31ecc528 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f9436144d7d RCX: 00007f94360c39f7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe31ecc5e0 RBP: 00007ffe31ecc5e0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe31ecd670 R13: 00007f9436144d7d R14: 000000000008bf2a R15: 00007ffe31ecd6b0 rcu: rcu_preempt kthread starved for 10052 jiffies! g49409 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:28064 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730 Code: bf 48 89 df e8 66 76 09 f8 eb b5 e8 9f af f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d 37 06 53 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffffff8be07dc8 EFLAGS: 000002c6 RAX: 9594ec4abd751700 RBX: ffffffff8bebc480 RCX: 9594ec4abd751700 RDX: 0000000000000001 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580 RBP: ffffffff8be07ef8 R08: dffffc0000000000 R09: ffffed1017207662 R10: ffffed1017207662 R11: 1ffff11017207661 R12: ffffffff8d699d28 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff17d7890 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112 cpuidle_idle_call kernel/sched/idle.c:194 [inline] do_idle+0x21b/0x5b0 kernel/sched/idle.c:306 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_kernel+0x486/0x530 init/main.c:1154 secondary_startup_64_no_verify+0xb1/0xbb IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available IPVS: fo: UDP 224.0.0.2:0 - no destination available ip6_tunnel: ip6gre1 xmit: Local address not yet configured!