mmdrv.exe failing vusers during execution - too much web_reg_save_param()??

Hi folks,

We have a complex web application with heavy parameterisation. We are trying a semi-automated recording/script-generation approach which creates many web_reg_save_param() calls. We are progressing, but when we execute our test in controller we see some virtual users die off with "LoadRunner has stopped working" popups & Event Log messages like "Faulting application name: mmdrv.exe, version: 12.55.639.0,...". We are wondering if all of this new parameterisation is responsible (the application can be scripted successfully with less, but is time consuming). 

So is there some kind of soft-limit to the number of dynamic parameters we can have? Or is it likely to cause some kind of memory violation/overflow as a secondary impact? Some of the parameters are very large, but most are not.

Any info welcomed.


  • Hi,

    Is it possible for you to share all the details of message "Faulting application name: mmdrv.exe, version: 12.55.639.0,..." in event viewer log?

  • Thanks for responding.

    I am actually posting for a colleague who is currently offline, but here is one I extracted - I will verify it is the same as current issue when colleague is available:

    Faulting application name: mmdrv.exe, version: 12.55.639.0, time stamp: 0x5972ace6
    Faulting module name: ntdll.dll, version: 10.0.14393.2969, time stamp: 0x5ccd12bb
    Exception code: 0xc0000374
    Fault offset: 0x000d9741
    Faulting process id: 0x1a6c
    Faulting application start time: 0x01d56cedf672e6fd
    Faulting application path: C:\Program Files (x86)\HPE\LoadRunner\bin\mmdrv.exe
    Faulting module path: C:\Windows\SYSTEM32\ntdll.dll
    Report Id: 12a11161-bfc7-4321-b535-bd0855e8e013
    Faulting package full name:
    Faulting package-relative application ID:

    Update - I can confirm the code & offset are consistent between failures. Things like timestamps vary, obviously.

  • The error Exception code: 0xc0000374 indicates Heap Corruption.

    I'm not sure if wrong handling of dynamic memory locations (malloc/free etc), or buffer overruns in your script can result in this type of error. I would focus on this type of issues in your script.

  • Thanks for response. My reasoning is that maybe there is some limit to the number of dynamic parameters or the amount of memory they consume in mmdrv & that in exceeding such limits our script is triggering the mmdrv failure.
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