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New crashes related to lib_burst_generated

Discussion in 'Data Oriented Technology Stack' started by davenirline, Jun 21, 2020.

  1. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    We just released an update to our game in early access and there's been lots of reports regarding crashes. I looked at our Crashes and Exceptions page and I see lib_burst_generated being mentioned:

    0 ntdll 0x00007ffa9629cbc4 ZwWaitForMultipleObjects
    1 KERNELBASE 0x00007ffa93f88037 WaitForMultipleObjectsEx
    2 KERNELBASE 0x00007ffa93f87f1e WaitForMultipleObjects
    3 UnityPlayer 0x00007ffa4c407ddd ?HandleCrash@ExternalCrashHandler@winutils@@AEAAXKKPEBDPEAU_CONTEXT@@PEAU_EXCEPTION_RECORD@@_N@Z
    4 UnityPlayer 0x00007ffa4c407e82 ?HandleCrash@ExternalCrashHandler@winutils@@QEAA_NKKPEAU_EXCEPTION_POINTERS@@@Z
    5 UnityPlayer 0x00007ffa4c414298 ?ProcessInternalCrash@winutils@@YAHPEAU_EXCEPTION_POINTERS@@_N@Z
    6 KERNELBASE 0x00007ffa9402feea UnhandledExceptionFilter
    7 ntdll 0x00007ffa962a4ab2 RtlUserThreadStart$filt$0
    8 ntdll 0x00007ffa9628c656 _C_specific_handler
    9 ntdll 0x00007ffa962a11cf RtlpExecuteHandlerForException
    10 ntdll 0x00007ffa9626a209 RtlDispatchException
    11 ntdll 0x00007ffa9629fe3e KiUserExceptionDispatch
    12 lib_burst_generated 0x00007ffa5cd3e01f <system symbols missing>
    13 lib_burst_generated 0x00007ffa5cd3ae63 <system symbols missing>
    14 lib_burst_generated 0x00007ffa5cd39e08 <system symbols missing>
    15 lib_burst_generated 0x00007ffa5cd39b30 <system symbols missing>
    16 lib_burst_generated 0x00007ffa5cd417b2 <system symbols missing>

    17 (Mono)
    18 (Mono)
    19 (Mono)
    20 (Mono)

    We're using Unity 2019.3.14, Unity.Entities 0.9.1. This hasn't happened for a while since I last reported (like a year ago). Was there any new changes related to Burst in build? Are there settings that I can tinker?
     
  2. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    Could this be the culprit:
    upload_2020-6-21_12-39-36.png

    Should I use Everything?
     
  3. tertle

    tertle

    Joined:
    Jan 25, 2011
    Posts:
    2,596
    This usually just means one of your burst jobs is throwing an exception (or ecb is)
     
  4. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    I don't think this is because some players can play the game fine while those machines where the game crashed did so in a particular moment (on starting a new game). Maybe on first run of a Burst compiled code. We also don't throw exceptions inside jobs, but I'll double check.
     
    Last edited: Jun 21, 2020
  5. tertle

    tertle

    Joined:
    Jan 25, 2011
    Posts:
    2,596
    From our experience, most exceptions and runtime crashes at runtime occurfrom

    In Jobs: GetComponent<T> calls on entities that don't have the component
    In ECB: Remove/Set component on an entity that does not exist (destroyed) or have component anymore.

    Both of these will just cause the application to hard crash with minimal details (unless safety system is on, then it'll still crash but you'll have better info.)

    However I have little experience with burst on mobile (all windows/consoles) so I am unaware if there are specific mobile specific issues.
     
  6. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    Thanks for the tips. The game is for Windows and Mac, btw.
     
  7. tertle

    tertle

    Joined:
    Jan 25, 2011
    Posts:
    2,596
    Get someone to crash on a development build and look at the dmp file. You'll find exactly what causes it.

    (though your issue does sound similar to what was in that other post instead of being a code issue)
     
    Last edited: Jun 21, 2020
  8. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    We've set these settings and our builds are reportedly no longer crashing:
    upload_2020-6-23_20-55-14.png

    We've tried setting to "Everything" but it still crashed on some machines.
     
  9. tertle

    tertle

    Joined:
    Jan 25, 2011
    Posts:
    2,596
    What version of burst out of interest?
    There was a bug in a 1.3 preview version (i want to say about 8) that was incorrectly identifying an instruction as avx instead of avx2
     
  10. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    Burst 1.3.0 preview.10
     
  11. davenirline

    davenirline

    Joined:
    Jul 7, 2010
    Posts:
    672
    Spoke too soon, we're still getting crash reports but only on old CPUs (2010 or before). But looking at one sample of the crash, the CPU has SSE2 and SSE4a support. The setting of our game should support it.

    Here's the crash report:
    upload_2020-7-1_12-2-51.png

    Here are the specs of the CPU.

    I have updated to the latest Unity (2019.4.1), Entities (0.11.1), and Burst 1.3.3 as candidate for players to test. Not sure yet if it will fix the problem.

    Some questions:
    What causes "Native Crash - Unknown Function (lib_burst_generated)"? Is it the Unity editor or the Burst version? I'm asking so we know which to upgrade or downgrade. Like use the latest Unity editor but outdated Burst.
     
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