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Tech Note: Crash in SymGetSymFromAddr64 from FWindowsPlatformStackWalk

Jan 19, 2021.Knowledge

Description:

4.26 and 4.25Plus sometimes exhibit a crash in SymGetSymFromAddr64 that’s called from FWindowsPlatformStackWalk. This occurs on the few latest versions of Visual Studio in the function WindowsPlatformStackWalk::ProgramCounterToSymbolInfo. This is due to an out of date dll that Epic is packaging with UE4.

This typically appears as a crash that looks like:

Access violation reading location 0x0000000000000000 UnrealEditor-Core-Win64-Debug.dll!FWindowsPlatformStackWalk::ProgramCounterToSymbolInfo(unsigned __int64 ProgramCounter, FProgramCounterSymbolInfo & out_SymbolInfo) Line 450 C++

Potential Impact:

Moderate: This has the potential to impact anyone using 4.25Plus or 4.26 on the latest few versions of Visual Studio. Some of the locations of these crashes include, but are not limited to, project test logging from within lambdas, the session frontend window being opened, and some instances of crash logging that get the program’s stack.

Solution:

This dll has since been updated and should be available as of 4.26.1, but to fix before this version:

Update [UE_Root]/Engine/Binaries/ThirdParty/DbgHelp/DbgHelp.dll with the attached dll, or integrate CL 14913031 from //UE4/Main, which does the same.

UE VERSION

4.25, 4.26

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