Exclude glibc libraries from dependency bundling

[TroyHernandez]

Summary

Excludes glibc libraries from the RUNTIME_DEPENDENCY_SET to prevent bundling system libraries that cause ABI conflicts on newer Linux distributions.

Problem

The current build bundles glibc 2.31 components from the Ubuntu 20.04 build environment:

• libc-2.31.so, libdl-2.31.so, libpthread-2.31.so, librt-2.31.so, libm-2.31.so, ld-2.31.so

When loaded on systems with newer glibc (e.g., Ubuntu 24.04 with glibc 2.39), GLIBC_PRIVATE symbol mismatches cause runtime failures:

liblantern.so - libdl.so.2: undefined symbol: _dl_catch_error, version GLIBC_PRIVATE

This manifests inconsistently depending on LD_LIBRARY_PATH ordering - if system library paths come first, system glibc wins and it works; otherwise the bundled glibc 2.31 gets loaded via liblantern.so's RUNPATH=$ORIGIN and fails.

Solution

Add PRE_EXCLUDE_REGEXES and POST_EXCLUDE_REGEXES to the install(RUNTIME_DEPENDENCY_SET ...) command to filter out:

• glibc library names (libc, libdl, libpthread, librt, libm, ld-linux)
• System library paths (/lib/, /lib64/, /usr/lib/)

glibc libraries should never be bundled on Linux - they must come from the host system. This is standard practice for portable Linux binaries (cf. manylinux approach).

Test plan

• Verify lantern builds successfully with BUNDLE_DEPENDENCIES=ON
• Confirm glibc libraries are not present in the resulting package
• Test on Ubuntu 24.04 (glibc 2.39) with various LD_LIBRARY_PATH configurations

Related issues

• torch fails to start on Alpine Linux #1323 (Alpine Linux glibc compatibility)
• Inconsistency detected by ld.so #663 (ld.so inconsistency)

---

Generated with Claude Code

[TroyHernandez]

Test Results

Build Test

Built and packaged lantern locally with BUNDLE_DEPENDENCIES=ON:

$ cmake .. -DBUNDLE_DEPENDENCIES=ON
$ cmake --build . --config Release --parallel 4 --target package
CPack: - package: lantern-0.16.3.9000+cpu+x86_64-Linux.zip generated.

Verified: No glibc libraries in package

$ unzip -l lantern-*.zip | grep -E 'libc-|libdl-|libpthread-|librt-|libm-|ld-.*\.so'
(no output - glibc excluded ✓)

Expected libraries still bundled:

libtorch_cpu.so, libtorch.so, liblantern.so, libc10.so, libgomp-*.so.1, etc.

Runtime Test

Replaced installed torch libs with the fixed build and tested both launchers:

Before fix (littler fails):

$ r -e 'library(torch)'
✖ liblantern.so - libdl.so.2: undefined symbol: _dl_catch_error, version GLIBC_PRIVATE

After fix (both work):

$ r -e 'library(torch); print(torch_tensor(1:5))'
torch_tensor
 1
 2
 3
 4
 5
[ CPULongType{5} ]

$ Rscript -e 'library(torch); print(torch_tensor(1:5))'
torch_tensor
 1
 2
 3
 4
 5
[ CPULongType{5} ]

Context: Why littler was affected

The issue manifests inconsistently because Rscript and littler set different LD_LIBRARY_PATH:

Launcher	LD_LIBRARY_PATH
Rscript	/usr/lib/R/lib:/usr/lib/x86_64-linux-gnu:... (system paths first)
littler	/usr/local/cuda-12.8/lib64:... (no system lib paths)

With system paths first, the loader finds system glibc before torch's bundled copy. Without them, liblantern.so's RUNPATH=$ORIGIN causes the bundled glibc 2.31 to be loaded, which fails against the system's glibc 2.39 due to GLIBC_PRIVATE symbol incompatibility.

This fix ensures the bundled package never includes glibc, so the loader always uses the host system's glibc regardless of LD_LIBRARY_PATH ordering.

Build Environment

• Ubuntu 24.04 (glibc 2.39)
• CMake 3.28.3
• GCC 13.3.0
• R 4.5.2