hytale-f2p/docs/STEAMDECK_CRASH_INVESTIGATION.md

Steam Deck / Ubuntu LTS Crash Investigation

Status: SOLVED

Last updated: 2026-01-27

Solution: Replace bundled libzstd.so with system version.

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Problem Summary

The Hytale F2P launcher's client patcher causes crashes on Steam Deck and Ubuntu LTS with the error:

free(): invalid pointer

or

SIGSEGV (Segmentation fault)

The crash occurs after successful authentication, specifically right after "Finished handling RequiredAssets".

Affected Systems:

• Steam Deck (glibc 2.41)
• Ubuntu LTS

Working Systems:

• macOS
• Windows
• Older Arch Linux (glibc < 2.41)

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Root Cause

The bundled libzstd.so in the game client is incompatible with glibc 2.41's stricter heap validation. When the game decompresses assets using this library, it triggers heap corruption detected by glibc 2.41.

The crash occurs in libzstd.so during free() after "Finished handling RequiredAssets" (asset decompression).

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Solution

Replace the bundled libzstd.so with the system's libzstd.so.1.

Automatic (Launcher)

The launcher automatically detects and replaces libzstd.so on Linux systems. No manual action needed.

Manual

cd ~/.hytalef2p/release/package/game/latest/Client

# Backup bundled version
mv libzstd.so libzstd.so.bundled

# Link to system version
# Steam Deck / Arch Linux:
ln -s /usr/lib/libzstd.so.1 libzstd.so

# Debian / Ubuntu:
ln -s /usr/lib/x86_64-linux-gnu/libzstd.so.1 libzstd.so

# Fedora / RHEL:
ln -s /usr/lib64/libzstd.so.1 libzstd.so

Restore Original

cd ~/.hytalef2p/release/package/game/latest/Client
rm libzstd.so
mv libzstd.so.bundled libzstd.so

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Why This Works

1. The bundled libzstd.so was likely compiled with different allocator settings or an older toolchain
2. glibc 2.41 has stricter heap validation that catches invalid memory operations
3. The system libzstd.so.1 is compiled with the system's glibc and uses compatible memory allocation patterns
4. By using the system library, we avoid the incompatibility entirely

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Previous Investigation (for reference)

What Was Tried Before Finding Solution

Approach	Result
jemalloc allocator	Worked ~30% of time, not stable
GLIBC_TUNABLES	No effect
taskset (CPU pinning)	Single core too slow
nice/chrt (scheduling)	No effect
Various patching approaches	All crashed

Key Insight

The crash was in libzstd.so, not in our patched code. The patching just changed timing enough to expose the libzstd incompatibility more frequently.

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GDB Stack Trace (Historical)

#0  0x00007ffff7d3f5a4 in ?? () from /usr/lib/libc.so.6
#1  raise () from /usr/lib/libc.so.6
#2  abort () from /usr/lib/libc.so.6
#3-#4  ?? () from /usr/lib/libc.so.6
#5  free () from /usr/lib/libc.so.6
#6  ?? () from libzstd.so    <-- CRASH POINT (bundled library)
#7-#24  HytaleClient code (asset decompression)

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Branch

fix/steamdeck-libzstd