rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5918/1:b..l rcu: (detected by 0, t=10502 jiffies, g=124105, q=1107 ncpus=2) task:kworker/1:5 state:R running task stack:20984 pid:5918 tgid:5918 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6908 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7235 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0xf4/0x1ea0 arch/x86/kernel/unwind_orc.c:498 Code: 7e 8e e8 4f e3 2c 00 e8 ba e0 d7 09 5a 85 c0 0f 85 16 06 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8d 65 50 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 08 17 00 00 4d 8b 75 50 4d 85 f6 74 36 49 8d be RSP: 0018:ffffc900043de750 EFLAGS: 00000a02 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000006 RDX: 1ffff9200087bd02 RSI: ffffffff8c1b03a0 RDI: ffffffff8e1278e8 RBP: ffffc900043de808 R08: 00000000aff8984b R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: ffffc900043de810 R13: ffffc900043de7c0 R14: 0000000000000000 R15: ffff88802a29c980 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 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5263 [inline] __kmalloc_node_track_caller_noprof+0x304/0x850 mm/slub.c:5371 __kmemdup_nul mm/util.c:64 [inline] kstrdup+0x51/0xe0 mm/util.c:84 kstrdup_const+0x63/0x80 mm/util.c:104 __kernfs_new_node+0x9b/0x960 fs/kernfs/dir.c:633 kernfs_new_node+0x11b/0x1a0 fs/kernfs/dir.c:718 kernfs_create_link+0xcc/0x240 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x90/0x140 fs/sysfs/symlink.c:44 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline] sysfs_create_link+0x61/0xc0 fs/sysfs/symlink.c:92 device_create_sys_dev_entry drivers/base/core.c:3515 [inline] device_add+0xb5d/0x1950 drivers/base/core.c:3659 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:583 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:661 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:961 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088 bus_probe_device+0x64/0x160 drivers/base/bus.c:574 device_add+0x11d9/0x1950 drivers/base/core.c:3689 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2208 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:583 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:661 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:961 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088 bus_probe_device+0x64/0x160 drivers/base/bus.c:574 device_add+0x11d9/0x1950 drivers/base/core.c:3689 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+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 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 10130 jiffies! g124105 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:26648 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7005 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+0x754/0xd80 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 02/27/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: a8 82 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 03 a1 1b 00 fb f4 fc 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: 0000000006fe8085 RBX: ffffffff8e4975c0 RCX: ffffffff8b8fec75 RDX: 0000000000000000 RSI: ffffffff8de763db RDI: ffffffff8c1b0420 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1017086795 R10: ffff8880b8433cab R11: 0000000000000000 R12: fffffbfff1c92eb8 R13: 0000000000000000 R14: ffffffff90d98d10 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124345000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2b39999dbd CR3: 0000000076171000 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:191 [inline] do_idle+0x43a/0x550 kernel/sched/idle.c:341 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:439 rest_init+0x251/0x260 init/main.c:760 start_kernel+0x47f/0x480 init/main.c:1210 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