rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6851/1:b..l P7966/1:b..l rcu: (detected by 1, t=10502 jiffies, g=40049, q=820 ncpus=2) task:syz.4.504 state:R running task stack:23400 pid:7966 tgid:7965 ppid:5641 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:81 [inline] RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:103 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x4fb/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: c1 e8 3f 48 01 c8 48 83 e0 fe 49 8d 1c 47 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 48 63 03 <48> 01 d8 48 8d 4b 04 48 39 e8 4c 0f 46 f9 48 8d 43 fc 4c 0f 47 e0 RSP: 0018:ffffc90005d56e60 EFLAGS: 00000246 RAX: fffffffff1af74a5 RBX: ffffffff9079abb0 RCX: dffffc0000000000 RDX: ffffffff9079ab98 RSI: ffffffff90fbf24a RDI: ffffffff8c4bd320 RBP: ffffffff82292004 R08: 000000000000000d R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: ffffffff9079abc8 R13: ffffffff9079ab98 R14: ffffc90005d56f08 R15: ffffffff9079ab98 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3294 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3408 new_slab mm/slub.c:3454 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7338 refill_sheaf mm/slub.c:2832 [inline] __pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4703 alloc_from_pcs mm/slub.c:4801 [inline] slab_alloc_node mm/slub.c:4933 [inline] kmem_cache_alloc_noprof+0x382/0x5f0 mm/slub.c:4959 f2fs_kmem_cache_alloc_nofail fs/f2fs/f2fs.h:3130 [inline] f2fs_kmem_cache_alloc fs/f2fs/f2fs.h:3140 [inline] add_free_nid+0xd7/0xb20 fs/f2fs/node.c:2431 scan_nat_page fs/f2fs/node.c:2532 [inline] __f2fs_build_free_nids fs/f2fs/node.c:2638 [inline] f2fs_build_free_nids+0xfdf/0x18c0 fs/f2fs/node.c:2684 f2fs_fill_super+0x4971/0x77f0 fs/f2fs/super.c:5236 get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1634 vfs_get_tree+0x92/0x2a0 fs/super.c:1694 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3765 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3841 do_mount fs/namespace.c:4174 [inline] __do_sys_mount fs/namespace.c:4390 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4367 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb0f4d9f0ca RSP: 002b:00007fb0f5be5e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fb0f5be5ee0 RCX: 00007fb0f4d9f0ca RDX: 0000200000000040 RSI: 0000200000000280 RDI: 00007fb0f5be5ea0 RBP: 0000200000000040 R08: 00007fb0f5be5ee0 R09: 000000000200841a R10: 000000000200841a R11: 0000000000000246 R12: 0000200000000280 R13: 00007fb0f5be5ea0 R14: 000000000000553b R15: 0000200000000f40 task:kworker/u8:12 state:R running task stack:23536 pid:6851 tgid:6851 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:debug_lockdep_rcu_enabled+0xd/0x40 kernel/rcu/update.c:320 Code: 8e 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 83 6d 88 04 00 <74> 1d 83 3d 5a 9f 88 04 00 74 14 65 48 8b 0d 58 75 9d 07 31 c0 83 RSP: 0018:ffffc900059ef0e8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffffff899feb56 RCX: 0000000000000046 RDX: 00000000b80462e8 RSI: ffffffff8e4af202 RDI: ffffffff8c4bd380 RBP: ffffc900059ef2f0 R08: ffffffff899feb56 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: ffff88807899e000 R13: 1ffff92000b3de28 R14: 0000000000000100 R15: ffffc900059ef160 rcu_read_lock include/linux/rcupdate.h:841 [inline] dev_get_alias+0x4b/0x250 net/core/dev.c:1573 nla_put_ifalias+0xf3/0x230 net/core/rtnetlink.c:1874 rtnl_fill_ifinfo+0x18fc/0x2750 net/core/rtnetlink.c:2134 rtmsg_ifinfo_build_skb+0x180/0x260 net/core/rtnetlink.c:4533 unregister_netdevice_many_notify+0x1865/0x2150 net/core/dev.c:12443 unregister_netdevice_many net/core/dev.c:12501 [inline] default_device_exit_batch+0x961/0x9e0 net/core/dev.c:13093 ops_exit_list net/core/net_namespace.c:205 [inline] ops_undo_list+0x4b4/0x8d0 net/core/net_namespace.c:252 cleanup_net+0x572/0x810 net/core/net_namespace.c:702 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 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: rcu_preempt kthread starved for 10543 jiffies! g40049 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7990 Comm: syz.0.511 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0033:0x7fc66133f1d7 Code: e8 ae 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 <0f> 05 0f 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b RSP: 002b:00007fc6621b9b40 EFLAGS: 00000206 RAX: 000000000000000f RBX: 00007fc661625fa8 RCX: 00007fc661397bd7 RDX: 00007fc6621b9b40 RSI: 00007fc6621b9c70 RDI: 0000000000000021 RBP: 00007fc661625fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fc661626038 R14: 00007ffefcac7d70 R15: 00007ffefcac7e58 FS: 00007fc6621ba6c0 GS: 0000000000000000