rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6098/1:b..l rcu: (detected by 1, t=10502 jiffies, g=13777, q=827 ncpus=2) task:kworker/u8:9 state:R running task stack:23512 pid:6098 tgid:6098 ppid:2 task_flags:0x4288060 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6786 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:unwind_next_frame+0x589/0x20a0 arch/x86/kernel/unwind_orc.c:512 Code: f2 40 0f 9e c6 84 d2 0f 95 c2 40 84 d6 0f 85 b8 13 00 00 41 83 e7 07 44 38 f8 0f 9e c2 84 c0 0f 95 c0 84 c2 0f 85 a1 13 00 00 <4c> 89 f2 44 0f b6 79 05 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 RSP: 0018:ffffc900042ff038 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff915273c2 RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffffff90c7bd38 RBP: ffffc900042ff0f0 R08: ffffffff915273c6 R09: 0000000000000000 R10: 0000000000000000 R11: 00000000000161d2 R12: ffffc900042ff0f8 R13: ffffc900042ff0a8 R14: ffffc900042ff0dd R15: 0000000000000007 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204 kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371 fill_pool lib/debugobjects.c:403 [inline] debug_objects_fill_pool lib/debugobjects.c:725 [inline] debug_objects_fill_pool+0x228/0x500 lib/debugobjects.c:697 debug_object_activate+0x10b/0x4c0 lib/debugobjects.c:814 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common.constprop.0+0x35/0xa10 kernel/rcu/tree.c:3079 kernfs_put.part.0+0x162/0x640 fs/kernfs/dir.c:591 kernfs_put fs/kernfs/dir.c:1724 [inline] kernfs_remove_by_name_ns+0xdf/0x110 fs/kernfs/dir.c:1718 kernfs_remove_by_name include/linux/kernfs.h:633 [inline] remove_files+0x96/0x1c0 fs/sysfs/group.c:28 sysfs_remove_group+0x8b/0x180 fs/sysfs/group.c:322 sysfs_remove_groups fs/sysfs/group.c:346 [inline] sysfs_remove_groups+0x60/0xa0 fs/sysfs/group.c:338 device_remove_groups drivers/base/core.c:2846 [inline] device_remove_attrs+0x203/0x290 drivers/base/core.c:2982 device_del+0x38e/0x9f0 drivers/base/core.c:3880 unregister_netdevice_many_notify+0x1903/0x2700 net/core/dev.c:12112 ops_exit_rtnl_list net/core/net_namespace.c:188 [inline] ops_undo_list+0x8fc/0xab0 net/core/net_namespace.c:249 cleanup_net+0x408/0x890 net/core/net_namespace.c:686 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 9687 jiffies! g13777 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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 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: 0 Comm: swapper/0 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: cb 6b 02 e9 83 fb 02 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 43 b9 21 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c6 RAX: 000000000274cb6d RBX: 0000000000000000 RCX: ffffffff8b885c99 RDX: 0000000000000000 RSI: ffffffff8de32e47 RDI: ffffffff8c158f60 RBP: fffffbfff1c52ef0 R08: 0000000000000001 R09: ffffed1017086645 R10: ffff8880b843322b R11: 0000000000000001 R12: 0000000000000000 R13: ffffffff8e297780 R14: ffffffff90a98750 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124713000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000e1a000 CR3: 0000000035bb1000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:749 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:745 start_kernel+0x3ee/0x4d0 init/main.c:1102 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x148