Assertion failed: refcnt >= 0, file core.c, line 1187, function libusb_unref_device

zoot # humility probe
Assertion failed: refcnt >= 0, file core.c, line 1187, function libusb_unref_device
Abort (core dumped)

zoot # pstack core | demangle
core 'core' of 676:     humility probe
 fffffc7feee185ba _lwp_kill () + a
 fffffc7feedac50e raise (6) + 1e
 fffffc7feed85f78 abort () + 58
 fffffc7feed863a2 ???????? ()
 fffffc7fef2db15f libusb_unref_device (3b130c0) + 5d
 fffffc7fef2dac2b libusb_free_device_list (39d3700, 1) + 33
 000000000288ef1a hid_enumerate () + 2fa
 0000000002888416 hidapi::HidApi::get_hid_device_info_vector::h4b96d00b44118d3f () + 56
 0000000002887e6a hidapi::HidApi::new::h063b2b1734428fce () + 3a
 0000000002773da2 probe_rs::probe::cmsisdap::tools::list_cmsisdap_devices::h748ad10f6547c97e () + 112
 0000000002725214 probe_rs::probe::Probe::list_all::he2ce4d6f57169bae () + 24
 00000000021d9877 humility_core::core::get_usb_probe::h1fbdd24ba2cb91be () + 27
 00000000021e345b humility_core::core::attach_to_chip::h02f68a44b9b50cfd () + cdb
 00000000021e3be1 humility_core::core::attach_to_chip::h02f68a44b9b50cfd () + 1461
 00000000021d9c2e humility_core::core::attach::h1e0ef0b014208b4b () + 7e
 0000000002071f64 humility_cmd::attach_live::h7f2eb12b511cf9b1 () + 84
 0000000001620dbf humility_cmd::attach::h62f2d7768e51e4cf () + 6f
 0000000001628bd3 humility::cmd::subcommand::hbf1a3b02f24ec77e () + 483
 000000000162c7cd humility::main::hb11b39981f545e3f () + b1d
 0000000001623426 std::sys_common::backtrace::__rust_begin_short_backtrace::hd98d37e970dea048 () + 6
 0000000001623471 std::rt::lang_start::_$u7b$$u7b$closure$u7d$$u7d$::h1f216740031e8cea (.llvm.6920345741585721526) () + 11
 00000000029d52a3 std::rt::lang_start_internal::h8e4b16a9f4a17dcc () + 2c3
 000000000162d453 main () + 33
 000000000160dc37 _start_crt () + 87
 000000000160db98 _start () + 18

zoot # humility --version
humility 0.10.39

Reproduce the failure with humility probe on the reported environment and inspect the stack from hid_enumerate through hidapi::HidApi::new and probe_rs::probe::cmsisdap::tools::list_cmsisdap_devices. Compare the device-list cleanup around the libusb_free_device_list call; done means probing no longer aborts with the libusb_unref_device assertion.