rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7852/1:b..l rcu: (detected by 0, t=10502 jiffies, g=44537, q=373 ncpus=2) task:syz-executor state:R running task stack:20992 pid:7852 tgid:7852 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5264 [inline] __schedule+0x1893/0x4b50 kernel/sched/core.c:6607 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6929 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x658/0xa30 kernel/locking/lockdep.c:5847 Code: 3c 3b 00 74 08 4c 89 f7 e8 95 f1 8b 00 f6 84 24 91 00 00 00 02 75 77 41 f7 c5 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 4b c7 44 27 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc90009037080 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92001206e22 RCX: ffffc90009037103 RDX: 0000000000000002 RSI: ffffffff8c0ae940 RDI: ffffffff8c60dd00 RBP: ffffc900090371b8 R08: ffffffff901c5aaf R09: 1ffffffff2038b55 R10: dffffc0000000000 R11: fffffbfff2038b56 R12: 1ffff92001206e1c R13: 0000000000000246 R14: ffffc90009037110 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] page_ext_put+0xa3/0xc0 mm/page_ext.c:550 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1102 [inline] free_unref_page+0xd36/0xea0 mm/page_alloc.c:2619 __slab_free+0x31b/0x3d0 mm/slub.c:4491 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x23/0xb0 mm/kasan/common.c:385 kasan_kmalloc include/linux/kasan.h:257 [inline] __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4296 kmalloc_noprof include/linux/slab.h:878 [inline] kzalloc_noprof include/linux/slab.h:1004 [inline] kobject_uevent_env+0x28b/0x8e0 lib/kobject_uevent.c:540 __kobject_del+0xd3/0x310 lib/kobject.c:601 kobject_cleanup lib/kobject.c:680 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x245/0x480 lib/kobject.c:737 netdev_queue_update_kobjects+0x4c3/0x550 net/core/net-sysfs.c:1857 remove_queue_kobjects net/core/net-sysfs.c:1954 [inline] netdev_unregister_kobject+0x110/0x250 net/core/net-sysfs.c:2107 unregister_netdevice_many_notify+0x1851/0x1da0 net/core/dev.c:11433 unregister_netdevice_many net/core/dev.c:11461 [inline] unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11335 unregister_netdevice include/linux/netdevice.h:3118 [inline] __tun_detach+0x6b9/0x1600 drivers/net/tun.c:685 tun_detach drivers/net/tun.c:701 [inline] tun_chr_close+0x105/0x1b0 drivers/net/tun.c:3517 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2f/0x27f0 kernel/exit.c:882 do_group_exit+0x207/0x2c0 kernel/exit.c:1031 get_signal+0x176f/0x1810 kernel/signal.c:2936 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fee6a974157 RSP: 002b:00007fee6ac5fd90 EFLAGS: 00000293 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 000000000000004c RCX: 00007fee6a974157 RDX: 0000000040000000 RSI: 00007fee6ac5fdec RDI: 00000000ffffffff RBP: 00007fee6ac5fdec R08: 0000000000000000 R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000293 R12: 0000555566c4d5eb R13: 0000555566c4d590 R14: 0000000000046b01 R15: 00007fee6ac5fe40 rcu: rcu_preempt kthread starved for 2499 jiffies! g44537 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:24464 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5264 [inline] __schedule+0x1893/0x4b50 kernel/sched/core.c:6607 __schedule_loop kernel/sched/core.c:6684 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6699 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111