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Fixed in 2020.2.X

Fixed in 2018.4.X, 2019.4.X, 2020.1.X



Found in




Issue ID




Editor crashes on mono_log_write_logfile when attaching a debugger and then setting a breakpoint



Reproduction steps:
1. Open the attached project ""
2. Enter Play mode
3. Open any script with Visual Studio 2019
4. Click on "Attach to Unity"
5. Set a breakpoint anywhere
6. If necessary, press "Switch to debug mode" in the Unity Editor and repeat the steps
-- Observe the crash

Reproduces on: 2019.3.11f1, 2020.1.0b8, 2020.2.0a10
Could not test with 2018.4 due to multiple compilation errors

- an assertion appears before the crash - "* Assertion at metadata.c:1117, condition `idx < t->rows' not met"
- reproduced both with Visual Studio 2019 and Rider

First 5 lines of the stack trace:
#0 0x007fff7281d7fa in __pthread_kill
#1 0x007fff727a4a1c in abort
#2 0x000001608f2f02 in mono_log_write_logfile
#3 0x00000160906f0c in monoeg_g_logv
#4 0x000001609070b1 in monoeg_assertion_message

  1. Resolution Note (fix version 2020.2):

    The mono debugger was hitting an assert when it attempted to parse a pdb that had zero sequence points this has been corrected in 2020.2.0a14

  2. Resolution Note (fix version 2020.1):

    Fixed in: 2020.1.0f1

  3. Resolution Note (fix version 2019.4):

    Fixed in: 2019.4.4f1

  4. Resolution Note (fix version 2018.4):

    Fixed in 2018.4.26f1

Comments (1)

  1. Alex-Thibodeau

    May 15, 2020 16:16

    This crash is caused by the PerformanceReportingModule pdb having zero sequence points for the mono debugger to parse which is causing Unity to hit an assert. Removing references to this library should work around the crash as it won't attempt to be parsed by the debugger.

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