[libusb] Libusb memory free error under windows?

[Dave C. <dav...@gm...>]

Hello libusb folks! :) I'm trying to track down an occasional bug that we
keep running into. For some reason, our application keeps crashing when
doing certain libusb related function calls. This only occurs on windows,
and appears to be modal. When it occurs, we can run our application
multiple times in a row, and it will keep crashing in the same way. If we
unplug all our USB devices, then plug them back in, then the problem
"disappears". At some point later, maybe with the same runtime instance,
maybe after a restart it will happen again. We are really not sure how to
reproduce it. It has happened with many users, on many different machines
(all windows) but we are not sure about the hardware distribution
statistics. The offending function call seems to be part of the process of
freeing memory, but we don't understand the implementation details of the
windows implementation to say why/how it's happening, or why it might be
modal.

Has anyone else seen this? Have suggestions? Thoughts?

Thanks,
-Dave


Technical Details:
- Libusb Version 1.0.21
- Libusb has been compiled under mingw
- Windows 10, 64bit, fully updated
- Stack Trace:
warning: Critical error detected c0000374

Thread 118 received signal SIGTRAP, Trace/breakpoint trap.
[Switching to Thread 8828.0x11fc]
0x00007ffc7b5b8243 in ntdll!RtlpNtMakeTemporaryKey () from
C:\WINDOWS\SYSTEM32\ntdll.dll
(gdb) backtrace
#0 0x00007ffc7b5b8243 in ntdll!RtlpNtMakeTemporaryKey () from
C:\WINDOWS\SYSTEM32\ntdll.dll
#1 0x00007ffc7b5b8bda in ntdll!RtlpNtMakeTemporaryKey () from
C:\WINDOWS\SYSTEM32\ntdll.dll
#2 0x00007ffc7b565b9a in ntdll!RtlRaiseStatus () from
C:\WINDOWS\SYSTEM32\ntdll.dll
#3 0x00007ffc7b4fc895 in ntdll!RtlFreeHeap () from
C:\WINDOWS\SYSTEM32\ntdll.dll
#4 0x00007ffc78c79dac in msvcrt!free () from C:\WINDOWS\System32\msvcrt.dll
#5 0x0000000066dd0033 in windows_get_device_list (ctx=0x177e1270,
_discdevs=0x2bacee08) at os/windows_winusb.c:1653
#6 0x0000000066dc539d in libusb_get_device_list (ctx=0x177e1270,
list=0x2bacef18) at core.c:842
#7 0x0000000066d61fb8 in apdm_usb_allocate_device_list
(dest_device_list=0x2bacf008) at apdm_usb.c:191

- Code Snipit from os/windows_winusb.c:1653
// Unref newly allocated devs
for (i = 0; i < unref_cur; i++)
safe_unref_device(unref_list[i]);
free(unref_list);