panic in Windows hotplug handler when usbipd bind/unbind is used

[Tiwalun]

I'm seeing a panic on Windows, when I bind or unbind a device in usbipd.

The panic happens on this unwrap:

nusb/src/platform/windows_winusb/hotplug.rs

Line 163 in 71b4425

.unwrap();

Steps to reproduce

• Start hotplug example
• Run usbipd bind or usbipd unbind
• hotplug example panics

Backtrace

``` thread '' (27932) panicked at src\platform\windows_winusb\hotplug.rs:163:14: called `Option::unwrap()` on a `None` value stack backtrace: 0: 0x7ff6610b40e2 - std::backtrace_rs::backtrace::win64::trace at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\..\..\backtrace\src\backtrace\win64.rs:85 1: 0x7ff6610b40e2 - std::backtrace_rs::backtrace::trace_unsynchronized at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66 2: 0x7ff6610b40e2 - std::sys::backtrace::_print_fmt at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\sys\backtrace.rs:68 3: 0x7ff6610b40e2 - std::sys::backtrace::impl$0::print::impl$0::fmt at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\sys\backtrace.rs:38 4: 0x7ff6610bcd21 - core::fmt::write at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\core\src\fmt\mod.rs:0 5: 0x7ff6610a8c84 - std::io::default_write_fmt at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\io\mod.rs:639 6: 0x7ff6610a8c84 - std::io::Write::write_fmt at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\io\mod.rs:1994 7: 0x7ff6610ae920 - std::sys::backtrace::BacktraceLock::print at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\sys\backtrace.rs:41 8: 0x7ff6610ae920 - std::panicking::default_hook::closure$0 at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\panicking.rs:292 9: 0x7ff6610ae738 - std::panicking::default_hook at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\panicking.rs:319 10: 0x7ff6610aeb92 - std::panicking::panic_with_hook at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\panicking.rs:825 11: 0x7ff6610aea29 - std::panicking::panic_handler::closure$0 at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\panicking.rs:691 12: 0x7ff6610acb0f - std::sys::backtrace::__rust_end_short_backtrace at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\sys\backtrace.rs:176 13: 0x7ff6610a745e - std::panicking::panic_handler at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\std\src\panicking.rs:689 14: 0x7ff6610c44ad - core::panicking::panic_fmt at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\core\src\panicking.rs:80 15: 0x7ff6610c4477 - core::panicking::panic at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\core\src\panicking.rs:150 16: 0x7ff6610c3fbe - core::option::unwrap_failed at /rustc/01f6ddf7588f42ae2d7eb0a2f21d44e8e96674cf/library\core\src\option.rs:2175 17: 0x7ff660df6498 - enum2$ >::unwrap at C:\Users\dboeh\.rustup\toolchains\stable-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\core\src\option.rs:1016 18: 0x7ff660df6498 - nusb::platform::windows_winusb::hotplug::hotplug_callback at C:\Users\dboeh\Coding\nusb\src\platform\windows_winusb\hotplug.rs:163 19: 0x7ffc6c0b89b1 - CM_Get_DevNode_Registry_Property_ExA 20: 0x7ffc6c0b8734 - CM_Get_DevNode_Registry_Property_ExA 21: 0x7ffc6c0be67d - SwDeviceGetLifetime 22: 0x7ffc6fc55240 - RtlSetThreadSubProcessTag 23: 0x7ffc6fc56291 - RtlSetThreadSubProcessTag 24: 0x7ffc6e69e8d7 - BaseThreadInitThunk 25: 0x7ffc6fc6c40c - RtlUserThreadStart error: process didn't exit successfully: `target\debug\examples\hotplug.exe` (exit code: 0xc0000409, STATUS_STACK_BUFFER_OVERRUN) ```

[kevinmehall]

Hmm, I'll have to try to reproduce this to see what those devices look like. In any case, that should probably ignore the notification rather than panicking, but I'm not sure why they would lack an instance ID or how we could correctly handle the event in that case.

[kevinmehall]

Oh, usbipd is the "server" side, sharing a local USB device, rather than an event for a remote device being attached. I tried usbipd 5.3.0 on Windows 10, and wasn't able to reproduce the panic because there was no hotplug event at all. Not sure why there should be an event in this case, because the device seems to remain usable locally after usbipd bind. (did not try connecting a usbip client to it).

#185 should make it ignore the event, though, and if you set $Env:RUST_LOG="nusb=debug" will log the event that it's seeing. Let me know if that works.

[Tiwalun]

I might have been a bit imprecise with the description, I'm using usbipd bind --force, because that's what usbipd is recommending:

❯ usbipd list
Connected:
BUSID  VID:PID    DEVICE                                                        STATE
1-4    046d:c52b  Logitech USB Input Device, USB-Eingabegerät                   Not shared
1-13   2e8a:000c  CMSIS-DAP v2 Interface, USB Serial Device (COM16)             Shared (forced)
1-20   05ac:0250  USB-Eingabegerät                                              Not shared
2-1    1d50:615b  USB Analyzer                                                  Not shared

Persisted:
GUID                                  DEVICE

usbipd: warning: USB filter 'USBPcap' is known to be incompatible with this software; 'bind --force' will be required.

The log from the PR:

[2026-02-22T07:56:53Z DEBUG nusb::platform::windows_winusb::hotplug] Hotplug callback: action=Connect, instance=USB\VID_2E8A&PID_000C\E6633861A374612C
[2026-02-22T07:56:53Z DEBUG nusb::platform::windows_winusb::enumeration] Probing device "USB\\VID_2E8A&PID_000C\\E6633861A374612C"
Connected(
    DeviceInfo {
        bus_id: "PCIROOT(0)#PCI(0103)#PCI(0000)#USBROOT(0)",
        device_address: 11,
        port_chain: [13],
        vendor_id: 0x2E8A,
        product_id: 0x000C,
        device_version: 0x0230,
        usb_version: 0x0210,
        class: 0x00,
        subclass: 0x00,
        protocol: 0x00,
        speed: Some(
            Full,
        ),
        manufacturer_string: None,
        product_string: Some(
            "Debug Probe (CMSIS-DAP)",
        ),
        serial_number: Some(
            "E6633861A374612C",
        ),
        instance_id: "USB\\VID_2E8A&PID_000C\\E6633861A374612C",
        parent_instance_id: "USB\\ROOT_HUB30\\5&3af988e2&0&0",
        location_paths: [
            "PCIROOT(0)#PCI(0103)#PCI(0000)#USBROOT(0)#USB(13)",
            "ACPI(_SB_)#ACPI(PCI0)#ACPI(GPP2)#ACPI(PTXH)#ACPI(RHUB)#ACPI(PO13)",
        ],
        port_number: 13,
        driver: Some(
            "VBoxUSB",
        ),
        interfaces: [
            InterfaceInfo {
                interface_number: 0,
                class: 0xFF,
                subclass: 0x00,
                protocol: 0x00,
                interface_string: None,
            },
            InterfaceInfo {
                interface_number: 1,
                class: 0x02,
                subclass: 0x02,
                protocol: 0x00,
                interface_string: None,
            },
            InterfaceInfo {
                interface_number: 2,
                class: 0x0A,
                subclass: 0x00,
                protocol: 0x00,
                interface_string: None,
            },
        ],
    },
)
[2026-02-22T07:57:30Z DEBUG nusb::platform::windows_winusb::hotplug] Failed to get device instance ID for hotplug Disconnect event on \\?\USB#VID_2E8A&PID_000C#E6633861A374612C#{a5dcbf10-6530-11d2-901f-00c04fb951ed}
[2026-02-22T07:57:31Z DEBUG nusb::platform::windows_winusb::hotplug] Hotplug callback: action=Connect, instance=USB\VID_2E8A&PID_000C\E6633861A374612C
[2026-02-22T07:57:31Z DEBUG nusb::platform::windows_winusb::enumeration] Probing device "USB\\VID_2E8A&PID_000C\\E6633861A374612C"
Connected(
    DeviceInfo {
        bus_id: "PCIROOT(0)#PCI(0103)#PCI(0000)#USBROOT(0)",
        device_address: 12,
        port_chain: [13],
        vendor_id: 0x2E8A,
        product_id: 0x000C,
        device_version: 0x0230,
        usb_version: 0x0210,
        class: 0x00,
        subclass: 0x00,
        protocol: 0x00,
        speed: Some(
            Full,
        ),
        manufacturer_string: None,
        product_string: Some(
            "Debug Probe (CMSIS-DAP)",
        ),
        serial_number: Some(
            "E6633861A374612C",
        ),
        instance_id: "USB\\VID_2E8A&PID_000C\\E6633861A374612C",
        parent_instance_id: "USB\\ROOT_HUB30\\5&3af988e2&0&0",
        location_paths: [
            "PCIROOT(0)#PCI(0103)#PCI(0000)#USBROOT(0)#USB(13)",
            "ACPI(_SB_)#ACPI(PCI0)#ACPI(GPP2)#ACPI(PTXH)#ACPI(RHUB)#ACPI(PO13)",
        ],
        port_number: 13,
        driver: Some(
            "usbccgp",
        ),
        interfaces: [
            InterfaceInfo {
                interface_number: 0,
                class: 0xFF,
                subclass: 0x00,
                protocol: 0x00,
                interface_string: None,
            },
            InterfaceInfo {
                interface_number: 1,
                class: 0x02,
                subclass: 0x02,
                protocol: 0x00,
                interface_string: None,
            },
            InterfaceInfo {
                interface_number: 2,
                class: 0x0A,
                subclass: 0x00,
                protocol: 0x00,
                interface_string: None,
            },
        ],
    },
)

It seems what's happening is that the driver changes between usbccgp and VBoxUSB.