rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21496/1:b..l rcu: (detected by 0, t=10502 jiffies, g=150765, q=1231 ncpus=2) task:syz-executor state:R running task stack:22312 pid:21496 tgid:21496 ppid:21481 task_flags:0x480140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x19d7/0x2550 arch/x86/kernel/unwind_orc.c:-1 Code: 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 b3 0a 00 00 48 0f bf 03 49 01 c4 49 8d 56 40 4c 89 f7 4c 89 e6 e8 1b 0e 00 00 84 c0 <0f> 84 46 01 00 00 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 20 0f RSP: 0018:ffffc900042d72f8 EFLAGS: 00000202 RAX: 1ffff9200085ae01 RBX: ffffffff90c5205c RCX: 0000000000000001 RDX: ffffc900042d7468 RSI: dffffc0000000000 RDI: ffffc900042d7418 RBP: dffffc0000000000 R08: ffffc900042d7418 R09: ffffc900042d7478 R10: dffffc0000000000 R11: fffff5200085ae91 R12: ffffc900042d7418 R13: 1ffff9200085ae87 R14: ffffc900042d7428 R15: 1ffffffff218a40b __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 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 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6250 [inline] kfree+0x1c5/0x640 mm/slub.c:6565 netif_free_rx_queues net/core/dev.c:11181 [inline] free_netdev+0x22e/0x6e0 net/core/dev.c:12185 __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_drv_remove+0x58/0x170 drivers/net/netdevsim/dev.c:1800 device_remove drivers/base/dd.c:619 [inline] __device_release_driver drivers/base/dd.c:1352 [inline] device_release_driver_internal+0x46f/0x870 drivers/base/dd.c:1375 bus_remove_device+0x455/0x570 drivers/base/bus.c:657 device_del+0x527/0x8f0 drivers/base/core.c:3895 device_unregister+0x21/0xf0 drivers/base/core.c:3936 nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline] del_device_store+0x2b0/0x370 drivers/net/netdevsim/bus.c:244 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fee8315d68e RSP: 002b:00007fff173980c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055556c36b500 RCX: 00007fee8315d68e RDX: 0000000000000001 RSI: 00007fff17398150 RDI: 0000000000000005 RBP: 00007fee832335f2 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fff17398150 R14: 00007fee83f44620 R15: 0000000000000003 rcu: rcu_preempt kthread timer wakeup didn't happen for 10295 jiffies! g150765 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=103816 rcu: rcu_preempt kthread starved for 10296 jiffies! g150765 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27536 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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:__run_hrtimer kernel/time/hrtimer.c:1896 [inline] RIP: 0010:__hrtimer_run_queues+0x1e5/0xa20 kernel/time/hrtimer.c:1994 Code: 8b 6c 24 30 4c 89 ef 48 89 de e8 b6 3b 13 00 49 39 dd 0f 8c 9a 07 00 00 48 8b 44 24 70 42 0f b6 04 38 84 c0 0f 85 e5 03 00 00 <8b> 1d 35 74 7e 0e 31 ff 89 de e8 6c 3d 13 00 85 db 4c 8b 6c 24 40 RSP: 0018:ffffc90000a08dd8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 18b178caea11b682 RCX: ffff88801daa0000 RDX: 0000000000010000 RSI: 18b178caea11b682 RDI: 1bc16d67510b7642 RBP: ffff88801ee92300 R08: ffff88801ee92317 R09: ffff88801ee92308 R10: dffffc0000000000 R11: ffffed1003dd2463 R12: ffff8880b8728280 R13: 1bc16d67510b7642 R14: ffff8880b8728420 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125389000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000001f000 CR3: 0000000032902000 CR4: 0000000000350ef0 Call Trace: 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:sched_core_balance+0xec/0xde0 kernel/sched/core.c:6419 Code: 00 4c 89 74 24 58 48 89 5c 24 40 4c 89 7c 24 08 e9 7e 0c 00 00 4c 89 f7 48 83 c7 48 e8 2d cc 15 0a e8 d8 ec 37 00 fb 83 fb 08 <0f> 83 4f 0c 00 00 4c 8d 34 dd 90 b7 26 8e 4c 89 f0 48 c1 e8 03 48 RSP: 0018:ffffc90000197aa0 EFLAGS: 00000297 RAX: 00000000026203fb RBX: 0000000000000001 RCX: 0000000080000002 RDX: 0000000000000000 RSI: ffffffff8dfac14f RDI: ffffffff8c28b660 RBP: dffffc0000000000 R08: ffffffff9030ccf7 R09: 1ffffffff206199e R10: dffffc0000000000 R11: fffffbfff206199f R12: ffff8880b873ae40 R13: 0000000000000000 R14: ffff8880b873ae40 R15: 0000000000000001 do_balance_callbacks kernel/sched/core.c:5018 [inline] __balance_callbacks kernel/sched/core.c:5074 [inline] finish_lock_switch kernel/sched/core.c:5123 [inline] finish_task_switch+0x5dd/0xbe0 kernel/sched/core.c:5243 context_switch kernel/sched/core.c:5391 [inline] __schedule+0x1829/0x5740 kernel/sched/core.c:7189 schedule_idle+0x51/0x90 kernel/sched/core.c:7309 do_idle+0x58a/0x5f0 kernel/sched/idle.c:381 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147