rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=83c4/1/0x4000000000000000 softirq=49033/49034 fqs=3 rcu: (detected by 1, t=10506 jiffies, g=58661, q=1198 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11598 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:check_preemption_disabled+0x1/0xe0 lib/smp_processor_id.c:13 Code: 00 b7 28 8c 48 c7 c6 40 b7 28 8c eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <41> 57 41 56 53 65 8b 05 27 ce 90 07 65 8b 0d 1c ce 90 07 f7 c1 ff RSP: 0018:ffffc90000007d18 EFLAGS: 00000086 RAX: 0000000000000001 RBX: 0000000000000000 RCX: b8707686c29149c1 RDX: 0000000028290900 RSI: ffffffff8e2168c0 RDI: ffffffff8c28b760 RBP: ffffffff81b27eca R08: ffffffff81b27eca R09: ffff8880b8628298 R10: dffffc0000000000 R11: fffffbfff206053f R12: 0000000000000000 R13: ffff8880b8628298 R14: 0000000000000001 R15: 0000000000000046 FS: 00005555819f8500(0000) GS:ffff88812529c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fda9552c080 CR3: 00000000367e9000 CR4: 0000000000350ef0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] lock_acquire+0x116/0x350 kernel/locking/lockdep.c:5870 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:174 __run_hrtimer kernel/time/hrtimer.c:1934 [inline] __hrtimer_run_queues+0x46a/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: ae 96 11 00 00 00 00 eb b5 e8 95 7d 05 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 75 68 96 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 45 69 6e ff cc 48 8d 3d f2 b3 91 RSP: 0018:ffffc90006ce7700 EFLAGS: 00000286 RAX: da59a9824da7db00 RBX: 0000000000000202 RCX: 0000000000000046 RDX: 0000000000000002 RSI: ffffffff8e2168c0 RDI: ffffffff8c28b760 RBP: ffff888032b2c9e0 R08: ffffc90006ce7cf0 R09: ffffc90006ce7858 R10: dffffc0000000000 R11: fffff52000d9cf0d R12: 0000000000000002 R13: 0000000000000002 R14: ffffffff8e95cc20 R15: ffff888032b2be00 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4918 __d_alloc+0x37/0x6f0 fs/dcache.c:1807 d_alloc+0x4b/0x190 fs/dcache.c:1886 lookup_one_qstr_excl+0xd8/0x360 fs/namei.c:1801 __start_dirop fs/namei.c:2916 [inline] start_dirop fs/namei.c:2938 [inline] filename_create+0x20e/0x370 fs/namei.c:4950 filename_symlinkat+0xf7/0x410 fs/namei.c:5662 __do_sys_symlinkat fs/namei.c:5688 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5683 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: 0033:0x7fda9559bf17 Code: 44 00 00 48 89 f2 31 c9 48 89 fe bf 9c ff ff ff e9 8e f5 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0a 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe49911328 EFLAGS: 00000202 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fda9559bf17 RDX: 00007fda95633d1d RSI: 00000000ffffff9c RDI: 00007fda9563279e RBP: 00007ffe4991136c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000e6 R13: 00000000000927c0 R14: 000000000008dba5 R15: 00007ffe499113c0 rcu: rcu_preempt kthread starved for 10490 jiffies! g58661 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:27968 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 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: CPU: 1 UID: 0 PID: 1157 Comm: kworker/u8:7 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: netns cleanup_net RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_single+0x3a4/0x5b0 kernel/smp.c:702 Code: e6 01 31 ff e8 5d 20 0c 00 41 83 e4 01 75 11 e8 12 1c 0c 00 4d 89 ec eb 41 e8 08 1c 0c 00 eb 3a 4d 89 ec f3 90 42 0f b6 04 33 <84> c0 75 10 41 f7 07 01 00 00 00 74 1e e8 ea 1b 0c 00 eb e5 44 89 RSP: 0018:ffffc900058b7360 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff92000b16e79 RCX: ffff888028b01f00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900058b7450 R08: ffffc900058b72a7 R09: 1ffff92000b16e54 R10: dffffc0000000000 R11: fffff52000b16e55 R12: 1ffff92000b16e74 R13: 1ffff92000b16e74 R14: dffffc0000000000 R15: ffffc900058b73c8 FS: 0000000000000000(0000) GS:ffff88812539c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe29dbff000 CR3: 0000000058e9b000 CR4: 0000000000350ef0 Call Trace: rcu_barrier+0x360/0x580 kernel/rcu/tree.c:3880 netdev_run_todo+0x2e0/0xde0 net/core/dev.c:11694 nsim_destroy+0x418/0x7f0 drivers/net/netdevsim/netdev.c:1200 __nsim_dev_port_del+0x14f/0x200 drivers/net/netdevsim/dev.c:1547 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1561 [inline] nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1785 nsim_dev_reload_down+0x8a/0xc0 drivers/net/netdevsim/dev.c:1038 devlink_reload+0x1eb/0x8c0 net/devlink/dev.c:462 devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:558 ops_pre_exit_list net/core/net_namespace.c:161 [inline] ops_undo_list+0x187/0x940 net/core/net_namespace.c:234 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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