rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=daf4/1/0x4000000000000000 softirq=67035/67035 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=105113, q=114 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 16492 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:mark_lock+0x18/0x190 kernel/locking/lockdep.c:4722 Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 8b 46 20 89 c1 81 e1 00 00 03 00 83 f9 01 09 00 00 00 83 db 00 83 fa 08 0f 45 da bd 01 00 00 00 89 d9 d3 RSP: 0018:ffffc90000a08b08 EFLAGS: 00000097 RAX: 00000000000c4000 RBX: ffff88803351abd8 RCX: 0000000000000000 RDX: 0000000000000008 RSI: ffff88803351abb8 RDI: ffff888033519ec0 RBP: 0000000000000000 R08: ffffffff84bc9e63 R09: ffffffff9a685810 R10: dffffc0000000000 R11: fffff520001411ac R12: 0000000000000002 R13: ffff88803351abb8 R14: ffff888033519ec0 R15: 0000000000000009 FS: 0000555572226500(0000) GS:ffff88812538d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000ed030 CR3: 000000007aa77000 CR4: 0000000000350ef0 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x6b5/0x2cf0 kernel/locking/lockdep.c:5191 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166 debug_object_activate+0x83/0x580 lib/debugobjects.c:835 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline] debug_activate kernel/time/hrtimer.c:528 [inline] enqueue_hrtimer+0xa9/0x2c0 kernel/time/hrtimer.c:1109 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x4d2/0xa20 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:__raw_read_unlock_irqrestore include/linux/rwlock_api_smp.h:266 [inline] RIP: 0010:_raw_read_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:272 Code: f7 e8 7d f7 f6 f5 f7 c3 00 02 00 00 74 05 e8 50 89 22 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 34 74 e8 f5 65 8b 05 2d cc 8d 07 85 c0 74 18 5b 41 5e e9 fc dc RSP: 0018:ffffc900058373a0 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000286 RCX: 0000000080000001 RDX: 0000000000000006 RSI: ffffffff8dfa66cf RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff9030b5f7 R09: 1ffffffff20616be R10: dffffc0000000000 R11: fffffbfff20616bf R12: dffffc0000000000 R13: ffff88801f6e2000 R14: ffffffff8fe3d4c0 R15: 0000000000000001 netlink_lock_table net/netlink/af_netlink.c:454 [inline] netlink_broadcast_filtered+0xbb/0xeb0 net/netlink/af_netlink.c:1530 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593 netif_close_many+0x284/0x420 net/core/dev.c:1804 netif_close_many_and_unlock net/core/dev.c:12312 [inline] unregister_netdevice_many_notify+0x825/0x22c0 net/core/dev.c:12382 unregister_netdevice_many net/core/dev.c:12481 [inline] unregister_netdevice_queue+0x31f/0x360 net/core/dev.c:12291 unregister_netdevice include/linux/netdevice.h:3444 [inline] nsim_destroy+0x277/0x7f0 drivers/net/netdevsim/netdev.c:1193 __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: 0033:0x7f5871d5d60e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007ffdb23d9e18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555572226500 RCX: 00007f5871d5d60e RDX: 0000000000000001 RSI: 00007ffdb23d9ea0 RDI: 0000000000000005 RBP: 00007f5871e335ec R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffdb23d9ea0 R14: 00007f5872b44620 R15: 0000000000000003 rcu: rcu_preempt kthread starved for 10500 jiffies! g105113 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:27544 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+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: CPU: 0 UID: 0 PID: 5627 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xfd4/0x13d0 kernel/smp.c:892 Code: 89 ee 83 e6 01 31 ff e8 da 07 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 85 03 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 6a 03 0c 00 eb e5 44 89 RSP: 0018:ffffc9000266f560 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b863c148 RCX: ffff88803351dc40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000266f688 R08: ffffffff9030b5f7 R09: 1ffffffff20616be R10: dffffc0000000000 R11: fffffbfff20616bf R12: 1ffff110170e8169 R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001 FS: 00005555784e8500(0000) GS:ffff88812528d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3431aff8 CR3: 000000005c69f000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c3/0x10b0 arch/x86/mm/tlb.c:1451 dup_mmap+0x17a2/0x1d90 mm/mmap.c:1905 dup_mm kernel/fork.c:1534 [inline] copy_mm+0x13b/0x4a0 kernel/fork.c:1586 copy_process+0x1f1c/0x4440 kernel/fork.c:2264 kernel_clone+0x284/0x8f0 kernel/fork.c:2721 __do_sys_clone kernel/fork.c:2862 [inline] __se_sys_clone kernel/fork.c:2846 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2846 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: 0033:0x7f7bf9bc5852 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe8edfcd80 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe8edfcd80 RCX: 00007f7bf9bc5852 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe8edfcf0c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555784e87d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 000000000008ae55 R15: 00007ffe8edfcf60