rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P29/1:b..l rcu: (detected by 0, t=10502 jiffies, g=37341, q=673 ncpus=2) task:kworker/1:1 state:R running task stack:21592 pid:29 tgid:29 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238 irqentry_exit+0x176/0x650 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x40/0x320 kernel/locking/lockdep.c:5879 Code: 2d ed 82 2a 12 48 89 6c 24 10 48 89 f5 0f 1f 44 00 00 65 8b 05 05 83 2a 12 83 f8 07 0f 87 1d 02 00 00 48 0f a3 05 d0 5c f5 0e <0f> 82 18 02 00 00 44 8b 05 97 90 f5 0e 45 85 c0 0f 84 48 01 00 00 RSP: 0018:ffffc90000a46638 EFLAGS: 00000297 RAX: 0000000000000001 RBX: ffffffff8e7e6b20 RCX: ffffffff91896401 RDX: 0000000000000000 RSI: ffffffff81b8103e RDI: ffffffff8e7e6b20 RBP: ffffffff81b8103e R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000018a27 R12: ffffc90000a46740 R13: ffffc90000a466f0 R14: ffffc90000a46f20 R15: ffffc90000a46724 rcu_lock_release include/linux/rcupdate.h:319 [inline] rcu_read_unlock include/linux/rcupdate.h:878 [inline] class_rcu_destructor include/linux/rcupdate.h:1190 [inline] unwind_next_frame+0x3c3/0x1ea0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4873 __kernfs_new_node+0xd2/0x9f0 fs/kernfs/dir.c:664 kernfs_new_node+0x11b/0x1a0 fs/kernfs/dir.c:748 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1057 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:313 sysfs_create_file_ns+0x145/0x1e0 fs/sysfs/file.c:374 sysfs_create_file include/linux/sysfs.h:774 [inline] device_create_file+0xf2/0x1d0 drivers/base/core.c:3056 device_add+0x2cb/0x1950 drivers/base/core.c:3638 cdev_device_add+0x12b/0x270 fs/char_dev.c:553 evdev_connect+0x3a8/0x4b0 drivers/input/evdev.c:1383 input_attach_handler.isra.0+0x177/0x1e0 drivers/input/input.c:994 input_register_device.cold+0x139/0x375 drivers/input/input.c:2378 usb_probe+0x1226/0x17c0 drivers/input/misc/yealink.c:928 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:851 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:881 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1009 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1081 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1136 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x11d9/0x1950 drivers/base/core.c:3691 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2266 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:851 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:881 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1009 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1081 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1136 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x11d9/0x1950 drivers/base/core.c:3691 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695 hub_port_connect drivers/usb/core/hub.c:5567 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x314d/0x4af0 drivers/usb/core/hub.c:5953 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3288 process_scheduled_works kernel/workqueue.c:3371 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3452 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 8007 jiffies! g37341 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:27832 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: f7 80 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 1f 19 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e407e00 EFLAGS: 00000242 RAX: 00000000018e5e79 RBX: ffffffff8e4975c0 RCX: ffffffff8b926d45 RDX: 0000000000000000 RSI: ffffffff8de8208a RDI: ffffffff8c1b62a0 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed101708679d R10: ffff8880b8433ceb R11: 0000000000000000 R12: 0000000000000000 R13: fffffbfff1c92eb8 R14: 0000000000000000 R15: ffffffff90da2a10 FS: 0000000000000000(0000) GS:ffff88812432b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d2dd012168 CR3: 0000000035d2a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:73 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x464/0x590 kernel/sched/idle.c:352 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451 rest_init+0x251/0x260 init/main.c:761 start_kernel+0x47f/0x480 init/main.c:1218 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148 sched: DL replenish lagged too much