from what i could tell the portion of code around line 365 is checking to see if a shader compile thread has finished ,
having same error on linux build …
[2022.01.03-10.52.05:536][ 0]LogCore: Error: appError called: Assertion failed: WaitingTask->IsCompleted() [File:Runtime/Core/Public/Tasks/TaskPrivate.h] [Line: 365]
[2022.01.03-10.52.05:830][ 0]LogCore: === Critical error: ===
Unhandled Exception: SIGSEGV: invalid attempt to write memory at address 0x0000000000000003
[2022.01.03-10.52.05:831][ 0]LogCore: Assertion failed: WaitingTask->IsCompleted() [File:Runtime/Core/Public/Tasks/TaskPrivate.h] [Line: 365]
…
given further up the log theres a number of threads that could cause this ie:-
[2022.01.03-10.51.57:260][ 0]LogMaterial: Display: Missing cached shadermap for HelpActorMaterial in VULKAN_SM5, Default, SM5 (DDC key hash: 6CD7DB2293D8FC8A4CE82440CD9D10CA7D406369), compiling.
i only skipped though the code to see what it appears to be doing , dont take my word as its been years since i did any c or c++ , but i would say it started the shader compile thread (with missing data ) and ether exited or suspended , the main thread not getting a exit or fail response for missing data
it leaves me to think the error arises as
1 files are failing to complete
2 the program fails to correctly note the fail
until it tries to test for the thread that it assumes is running but is no longer there
as in no exit success ,and exit fail does not look to be tested for and just tries to probe a none existent thread ( causing segfault )
given the name of some of those files like “HelpActorMaterial” ,“DefaultTextMaterialOpaque” to name but 2 of the 7 or 8 commenting them out looks to me like it will only move the issue or make it a bigger issue later and not solve the problem
… update , the files are there apparently under ~UnrealEngine5/Engine/Content/EditorMaterials , wrong place ? or some other issue ? would need debug message from the thread to see whats happening when processing them i guess
from reading the forum this seems to be / has been a issue on ue4 builds also in the past ,but no solution to it there that could help me solve it , 