rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (9130 ticks this GP) idle=2724/1/0x4000000000000000 softirq=56611/56611 fqs=4788 rcu: hardirqs softirqs csw/system rcu: number: 5124 5780 2 rcu: cputime: 0 324 38509 ==> 52550(ms) rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6097/1:b..l rcu: (detected by 0, t=11895 jiffies, g=71317, q=852 ncpus=2) task:kworker/1:7 state:R running task stack:22856 pid:6097 tgid:6097 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0xf89/0x4840 kernel/sched/core.c:7188 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x1cc/0x6c0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:231 Code: 00 00 85 c0 74 f1 8b 82 e0 15 00 00 83 f8 02 75 e6 48 8b 8a e8 15 00 00 8b 92 e4 15 00 00 48 8b 01 48 83 c0 01 48 39 d0 73 cd <48> 89 01 48 89 34 c1 e9 d7 bb bd 05 0f 1f 80 00 00 00 00 90 90 90 RSP: 0018:ffffc900131cee68 EFLAGS: 00000287 RAX: 0000000000082717 RBX: ffff888112ec5780 RCX: ffffc9000fd86000 RDX: 0000000000100000 RSI: ffffffff824867f4 RDI: ffff8881154f3b80 RBP: ffff888106bbc960 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888100e87918 R14: 0000000000000000 R15: ffff888100e87918 kernfs_root+0x94/0x2a0 fs/kernfs/kernfs-internal.h:76 kernfs_next_descendant_post+0x1f5/0x4b0 fs/kernfs/dir.c:1411 kernfs_activate fs/kernfs/dir.c:1466 [inline] kernfs_add_one+0x56e/0x850 fs/kernfs/dir.c:869 __kernfs_create_file+0x295/0x350 fs/kernfs/file.c:1086 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x593/0xf40 fs/sysfs/group.c:189 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:229 really_probe+0x2b1/0xa60 drivers/base/dd.c:728 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268 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+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 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+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 1403 jiffies! g71317 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=21037 rcu: rcu_preempt kthread starved for 1458 jiffies! g71317 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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 stack:28360 pid:15 tgid:15 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0xf89/0x4840 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 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+0x69a/0xc80 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 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: b4 b7 01 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 63 4d 19 00 fb f4 bc f2 02 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff89407e10 EFLAGS: 00000246 RAX: 000000000094f2db RBX: ffffffff8942ca40 RCX: ffffffff876d33f5 RDX: 0000000000000000 RSI: ffffffff890c4e9f RDI: ffffffff87b04160 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed103eac673d R10: ffff8881f56339eb R11: 0000000000000000 R12: 0000000000000000 R13: fffffbfff1285948 R14: 0000000000000000 R15: ffffffff8af099d0 FS: 0000000000000000(0000) GS:ffff8882686a9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f256d991c64 CR3: 0000000116a58000 CR4: 00000000003506f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:62 [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:762 start_kernel+0x47f/0x480 init/main.c:1220 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 raw-gadget.5 gadget.1: ignoring, device is not running