Purpose of nydus.dll and Availability of Debugging Symbols

Description : I’m troubleshooting a customer-reported crash in the Zoom Desktop Client for Windows and discovered crash dumps in the client’s log folders that indicate an access violation when nydus.dll tries to enter a critical section. This DLL also seems to be included with the Meeting SDK when I downloaded version 5.9.7.3953, and I’m trying to get some general information about what this library does and how to interpret stack traces involving it (like public symbols for use in debuggers like WinDbg).

I’m not actually writing an application that uses the Meeting SDK, but thought the SDK might contain some useful information for troubleshooting, since the Zoom Desktop Client might use it internally.

SDK Version : nydus.dll is showing version 5.10.10.4306.

Reproducible Steps : Not sure yet; this is based on customer testimony.

Device Information :
Device Type: Desktop PC
OS: Windows 10 Version 19043 MP (16 procs) Free x86 compatible
Version: 19041.1.amd64fre.vb_release.191206-1406
Additional Context :

CONTEXT:  (.ecxr)
eax=00000000 ebx=fffffffa ecx=ffffffff edx=fffffffa esi=2c1c2d7c edi=2c1c2d6c
eip=77def563 esp=2d22f1a0 ebp=2d22f230 iopl=0         nv up ei pl nz ac po cy
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010213
ntdll!RtlpWaitOnCriticalSection+0x93:
77def563 ff4014          inc     dword ptr [eax+14h]  ds:002b:00000014=????????
Resetting default scope

EXCEPTION_RECORD:  (.exr -1)
ExceptionAddress: 77def563 (ntdll!RtlpWaitOnCriticalSection+0x00000093)
   ExceptionCode: c0000005 (Access violation)
  ExceptionFlags: 00000000
NumberParameters: 2
   Parameter[0]: 00000001
   Parameter[1]: 00000014
Attempt to write to address 00000014

PROCESS_NAME:  Zoom.exe

WRITE_ADDRESS:  00000014 

ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p referenced memory at 0x%p. The memory could not be %s.

EXCEPTION_CODE_STR:  c0000005

EXCEPTION_PARAMETER1:  00000001

EXCEPTION_PARAMETER2:  00000014

STACK_TEXT:  
2d22f230 77dd00ca     2c1c2d50 2c1c2d6c 2c1c9870 ntdll!RtlpWaitOnCriticalSection+0x93
2d22f268 77dcff19     2d22f2b8 7bed7c1b 2c1c2d6c ntdll!RtlpEnterCriticalSectionContended+0x1aa
2d22f270 7bed7c1b     2c1c2d6c f5333f00 00000000 ntdll!RtlEnterCriticalSection+0x49
WARNING: Stack unwind information not available. Following frames may be wrong.
2d22f2b8 7befb190     00b56800 00000000 2d22f320 nydus+0x97c1b
2d22f2d4 7befb140     00b56800 7bf99a28 2d22f330 nydus+0xbb190
2d22f2e4 7be540d4     2c1c2d8c 00b56800 2d22f320 nydus+0xbb140
2d22f330 2ce55e59     2d22f35c 2d22f358 00b56800 nydus+0x140d4
2d22f360 2ce56495     2d22f61c 2d22f4e0 2c247bc0 zlt+0x205e59
2d22f3bc 2ce55d82     2d22f61c 2d22f4c8 2c247bc0 zlt+0x206495
2d22f3d4 2ce4e660     2d22f61c 2d22f4c8 0cca96dc zlt+0x205d82
2d22f538 7be5442f     2d22f5a0 2d22f61c f5333b7c zlt+0x1fe660
2d22f6c4 7be5fd0f     2d22f708 2d22f74c 2c1c96dc nydus+0x1442f
2d22f784 7be5f277     2d22f7e0 00000000 4dd532d0 nydus+0x1fd0f
2d22f824 7beda617     2c1c96b0 7beda600 2d22f86c nydus+0x1f277
2d22f834 77c34f9f     2c1c97bc 9d76848b 77c34f60 nydus+0x9a617
2d22f86c 776dfa29     1eb35bd0 776dfa10 2d22f8d8 ucrtbase!thread_start<unsigned int (__stdcall*)(void *),1>+0x3f
2d22f87c 77df7a7e     1eb35bd0 f96fba3f 00000000 kernel32!BaseThreadInitThunk+0x19
2d22f8d8 77df7a4e     ffffffff 77e18a32 00000000 ntdll!__RtlUserThreadStart+0x2f
2d22f8e8 00000000     77c34f60 1eb35bd0 00000000 ntdll!_RtlUserThreadStart+0x1b


SYMBOL_NAME:  nydus+97c1b

MODULE_NAME: nydus

IMAGE_NAME:  nydus.dll

STACK_COMMAND:  ~47s; .ecxr ; kb

FAILURE_BUCKET_ID:  NULL_CLASS_PTR_WRITE_c0000005_nydus.dll!Unknown

OS_VERSION:  10.0.19041.1

BUILDLAB_STR:  vb_release

OSPLATFORM_TYPE:  x86

OSNAME:  Windows 10

IMAGE_VERSION:  5.10.0.4306

FAILURE_ID_HASH:  {b2866861-092c-1cb1-38fe-6c88ac125783}

Followup:     MachineOwner
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