[WIP] @eunomia-bpf/bpf-developer-tutorial/issues/148 can you check it?

BLAZESYM_BUILD_WORKAROUND.md

@@ -0,0 +1,77 @@
+# Blazesym Build Workaround for ARM64 Platforms
+
+This document provides workarounds for the blazesym build issue reported in [issue #148](https://github.com/eunomia-bpf/bpf-developer-tutorial/issues/148).
+
+## Issue Description
+
+When building blazesym with the `cheader` feature on ARM64 (aarch64) platforms, you may encounter the following error:
+
+```
+/usr/bin/ld: discarded output section: `.got.plt'
+collect2: error: ld returned 1 exit status
+```
+
+This error occurs because the linker script used for generating test files is too aggressive in discarding sections, including the `.got.plt` section which is essential on ARM64 platforms.
+
+## Solution
+
+**The tutorial repository already includes a workaround for this issue.** The examples that use blazesym (like `src/12-profile` and `src/16-memleak`) are configured to use the `dont-generate-test-files` feature flag when building blazesym.
+
+You can see this in their Makefiles:
+```makefile
+$(LIBBLAZESYM_SRC)/target/release/libblazesym.a::
+	$(Q)cd $(LIBBLAZESYM_SRC) && $(CARGO) build --features=cheader,dont-generate-test-files --release
+```
+
+## If You Encounter This Issue
+
+### For Tutorial Examples
+Simply use the provided Makefiles:
+```bash
+cd src/12-profile  # or src/16-memleak
+make
+```
+
+### For Manual Blazesym Building
+If you need to build blazesym manually, use the `dont-generate-test-files` feature:
+
+```bash
+cd src/third_party/blazesym
+cargo build --features=cheader,dont-generate-test-files
+```
+
+### Alternative Workarounds
+
+1. **Skip C Header Generation** (if you don't need C headers):
+   ```bash
+   cd src/third_party/blazesym
+   cargo build
+   ```
+
+2. **Install LLVM Tools** (if you want full test support):
+   ```bash
+   # On Ubuntu/Debian:
+   sudo apt install llvm
+
+   # Then build normally:
+   cargo build --features=cheader
+   ```
+
+## Technical Details
+
+The issue is caused by the linker script in `data/test-gsym.ld` being too aggressive in discarding sections. On ARM64 platforms, the `.got.plt` section is essential and cannot be discarded.
+
+The `dont-generate-test-files` feature flag bypasses the generation of test files that require this problematic linker script, allowing blazesym to build successfully while maintaining all core functionality.
+
+## Impact
+
+- **Core blazesym functionality**: ✅ Not affected
+- **C header generation**: ✅ Works with the workaround
+- **Test file generation**: ⚠️ Skipped on problematic platforms
+- **Symbol resolution**: ✅ Works normally
+
+## References
+
+- [Issue #148](https://github.com/eunomia-bpf/bpf-developer-tutorial/issues/148)
+- [Blazesym Repository](https://github.com/libbpf/blazesym)
+- [ARM64 GOT/PLT Documentation](https://developer.arm.com/documentation/dui0803/j/ELF-features/Global-Offset-Table--GOT-)

README.md

@@ -168,6 +168,12 @@ cd src/24-hide
 make
 ```
 
+## Known Issues
+
+### ARM64 Build Issue with Blazesym
+
+If you encounter build errors on ARM64 (aarch64) platforms related to blazesym, see [BLAZESYM_BUILD_WORKAROUND.md](BLAZESYM_BUILD_WORKAROUND.md) for solutions. The tutorial examples are already configured with appropriate workarounds.
+
 ## LICENSE
 
 MIT