rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=e854/1/0x4000000000000000 softirq=93499/93500 fqs=1 rcu: (detected by 1, t=10506 jiffies, g=70633, q=676 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6688 Comm: kworker/u8:7 Not tainted 6.15.0-syzkaller-03589-gfeacb1774bd5 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: netns cleanup_net RIP: 0010:preempt_count_add+0x0/0x150 kernel/sched/core.c:5857 Code: ff 1e 12 75 0f 48 83 ec 80 5b 5d 41 5c 41 5d e9 56 56 ef 09 e8 f1 5d ec 09 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 c7 c0 c0 70 b7 9a 55 48 ba 00 00 00 00 00 fc ff df RSP: 0018:ffffc90000007e28 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffff8880b8427c40 RCX: ffffffff81a84e1a RDX: ffff88802378c880 RSI: ffffffff81a848c4 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff8880b8427c40 R13: 0000000000000001 R14: ffff888031cb2340 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812499f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbce9fb7bac CR3: 000000005997c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:118 [inline] _raw_spin_lock_irq+0x1a/0x50 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1765 [inline] __hrtimer_run_queues+0x2bc/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_preemption_disabled+0xf/0xe0 lib/smp_processor_id.c:16 Code: 0f 0b 90 e9 53 fc ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 54 55 53 48 83 ec 08 65 8b 1d c5 87 32 08 <65> 8b 05 ba 87 32 08 a9 ff ff ff 7f 74 0f 48 83 c4 08 89 d8 5b 5d RSP: 0018:ffffc9000b9fed88 EFLAGS: 00000296 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffc9000ba00001 RDX: ffffc9000b9ff190 RSI: ffffffff8bf51380 RDI: ffffffff8bf513c0 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000012189 R12: ffffc9000b9fee88 R13: ffffc9000b9fee38 R14: ffffc9000b9ff188 R15: ffffc9000b9fee6c rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:745 rcu_read_unlock include/linux/rcupdate.h:869 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xa92/0x20a0 arch/x86/kernel/unwind_orc.c:479 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:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4203 __kernfs_new_node+0xd2/0x8a0 fs/kernfs/dir.c:637 kernfs_new_node+0x13c/0x1e0 fs/kernfs/dir.c:713 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1038 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:319 create_files fs/sysfs/group.c:76 [inline] internal_create_group+0x578/0xf30 fs/sysfs/group.c:183 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:223 device_add_groups drivers/base/core.c:2839 [inline] device_add_attrs drivers/base/core.c:2903 [inline] device_add+0x6d1/0x1a70 drivers/base/core.c:3646 netdev_register_kobject+0x182/0x3a0 net/core/net-sysfs.c:2336 register_netdevice+0x13dc/0x2270 net/core/dev.c:10999 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:960 [inline] nsim_create+0xc70/0x10a0 drivers/net/netdevsim/netdev.c:1028 __nsim_dev_port_add+0x42b/0x7d0 drivers/net/netdevsim/dev.c:1393 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1449 [inline] nsim_dev_reload_create drivers/net/netdevsim/dev.c:1501 [inline] nsim_dev_reload_up+0x5b5/0x860 drivers/net/netdevsim/dev.c:988 devlink_reload+0x322/0x7c0 net/devlink/dev.c:474 devlink_pernet_pre_exit+0x1a0/0x2b0 net/devlink/core.c:509 ops_pre_exit_list net/core/net_namespace.c:162 [inline] cleanup_net+0x494/0xb30 net/core/net_namespace.c:634 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+0x5d4/0x6f0 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 10500 jiffies! g70633 f0x0 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:27688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6874 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+0x5d4/0x6f0 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: CPU: 1 UID: 0 PID: 5900 Comm: kworker/1:7 Not tainted 6.15.0-syzkaller-03589-gfeacb1774bd5 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events drain_vmap_area_work RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xd0f/0x1490 kernel/smp.c:885 Code: 00 45 85 ed 74 46 48 8b 14 24 49 89 d6 49 89 d5 49 c1 ee 03 41 83 e5 07 4d 01 e6 41 83 c5 03 e8 47 13 0c 00 f3 90 41 0f b6 06 <41> 38 c5 7c 08 84 c0 0f 85 6f 05 00 00 8b 43 08 31 ff 83 e0 01 89 RSP: 0018:ffffc90005537a48 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8441ec0 RCX: ffffffff81af614d RDX: ffff888029742440 RSI: ffffffff81af6129 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed10170883d9 R15: ffff8880b853b4c0 FS: 0000000000000000(0000) GS:ffff888124a9f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fedfdf7d2d8 CR3: 000000005997c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] kernel_tlb_flush_all arch/x86/mm/tlb.c:1517 [inline] flush_tlb_kernel_range+0x1d6/0x220 arch/x86/mm/tlb.c:1538 __purge_vmap_area_lazy+0x502/0xc90 mm/vmalloc.c:2284 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2338 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+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245