Trouble fuzzing on macos #31111

I've got a Apple M2 Max macbook pro, running sequoia 15.0.1. I'm trying to follow the instructions for fuzzing on macos, but I'm running into trouble.

I reinstalled llvm via brew install, as the instructions indicated:

$ clang --version
Homebrew clang version 19.1.2
Target: arm64-apple-darwin24.0.0
Thread model: posix
InstalledDir: /opt/homebrew/Cellar/llvm/19.1.2/bin
$ clang++ --version
Homebrew clang version 19.1.2
Target: arm64-apple-darwin24.0.0
Thread model: posix
InstalledDir: /opt/homebrew/Cellar/llvm/19.1.2/bin

I've got our master branch checked out at e8f72aefd20049eac81b150e7f0d33709acd18ed:

$ git log --oneline -1
e8f72aefd20 (HEAD -> 2024-10-master, origin/master, origin/HEAD) Merge bitcoin/bitcoin#29877: tracing: explicitly cast block_connected duration to nanoseconds

And when I try to fuzz with the instructed preset, I get this:

$ cmake --preset=libfuzzer-nosan
Preset CMake variables:

  BUILD_FOR_FUZZING="ON"
  CMAKE_CXX_COMPILER="clang++"
  CMAKE_C_COMPILER="clang"
  SANITIZERS="fuzzer"

-- The CXX compiler identification is Clang 19.1.2
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /opt/homebrew/opt/llvm/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found SQLite3: /Library/Developer/CommandLineTools/SDKs/MacOSX15.0.sdk/usr/include (found suitable version "3.43.2", minimum required is "3.7.17")
CMake Warning at CMakeLists.txt:227 (message):
  BUILD_FOR_FUZZING=ON will disable all other targets and force
  BUILD_FUZZ_BINARY=ON.


-- Performing Test CXX_SUPPORTS__WERROR
-- Performing Test CXX_SUPPORTS__WERROR - Success
-- Setting build type to "RelWithDebInfo" as none was specified
-- Performing Test CXX_SUPPORTS__G3
-- Performing Test CXX_SUPPORTS__G3 - Success
-- Performing Test LINKER_SUPPORTS__G3
-- Performing Test LINKER_SUPPORTS__G3 - Success
-- Performing Test CXX_SUPPORTS__FTRAPV
-- Performing Test CXX_SUPPORTS__FTRAPV - Success
-- Performing Test LINKER_SUPPORTS__FTRAPV
-- Performing Test LINKER_SUPPORTS__FTRAPV - Success
-- Performing Test LINKER_SUPPORTS__WL__FATAL_WARNINGS
-- Performing Test LINKER_SUPPORTS__WL__FATAL_WARNINGS - Success
-- Performing Test LINKER_SUPPORTS__WL__DEAD_STRIP
-- Performing Test LINKER_SUPPORTS__WL__DEAD_STRIP - Success
-- Performing Test LINKER_SUPPORTS__WL__DEAD_STRIP_DYLIBS
-- Performing Test LINKER_SUPPORTS__WL__DEAD_STRIP_DYLIBS - Success
-- Performing Test LINKER_SUPPORTS__WL__HEADERPAD_MAX_INSTALL_NAMES
-- Performing Test LINKER_SUPPORTS__WL__HEADERPAD_MAX_INSTALL_NAMES - Success
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- Performing Test CXX_SUPPORTS__FSANITIZE_FUZZER
-- Performing Test CXX_SUPPORTS__FSANITIZE_FUZZER - Success
-- Performing Test LINKER_SUPPORTS__FSANITIZE_FUZZER_a797
-- Performing Test LINKER_SUPPORTS__FSANITIZE_FUZZER_a797 - Failed
CMake Error at CMakeLists.txt:377 (message):
  Linker did not accept requested flags, you are missing required libraries.


-- Configuring incomplete, errors occurred!

Any suggestions for what I should try next?

From https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md#macos-hints-for-libfuzzer:

brew install llvm

...

$ cmake --preset=libfuzzer -DCMAKE_C_COMPILER="$(brew --prefix llvm)/bin/clang" -DCMAKE_CXX_COMPILER="$(brew --prefix llvm)/bin/clang++" -DAPPEND_LDFLAGS=-Wl,-no_warn_duplicate_libraries

Thanks, I actually had tried that but got some kind of failure as well. Starting over and trying that step now, I see that the first step of setting up the build_fuzz directory succeeds, but when I try to build, I get this linker error:

$ cmake --build build_fuzz/ -j12
<snip>
[ 99%] Building CXX object src/test/fuzz/CMakeFiles/fuzz.dir/__/__/wallet/test/fuzz/scriptpubkeyman.cpp.o
[ 99%] Building CXX object src/test/fuzz/CMakeFiles/fuzz.dir/__/__/wallet/test/fuzz/wallet_bdb_parser.cpp.o
[100%] Linking CXX executable fuzz
ld: multiple errors: invalid r_symbolnum=1 in '/Users/sdaftuar/projects/bitcoin/2024-10-master/build_fuzz/src/test/fuzz/CMakeFiles/fuzz.dir/addition_overflow.cpp.o'; invalid r_symbolnum=1 in '/Users/sdaftuar/projects/bitcoin/2024-10-master/build_fuzz/src/test/fuzz/CMakeFiles/fuzz.dir/fees.cpp.o'; invalid r_symbolnum=1 in '/Users/sdaftuar/projects/bitcoin/2024-10-master/build_fuzz/src/test/fuzz/CMakeFiles/fuzz.dir/float.cpp.o'; invalid r_symbolnum=1 in '/Users/sdaftuar/projects/bitcoin/2024-10-master/build_fuzz/src/test/fuzz/CMakeFiles/fuzz.dir/multiplication_overflow.cpp.o'; invalid r_symbolnum=1 in '../../libbitcoin_cli.a[2](stdin.cpp.o)'; invalid r_symbolnum=1 in '../../../libcrc32c.a[3](crc32c_portable.cc.o)'; invalid r_symbolnum=1 in '../../../libcrc32c.a[2](crc32c.cc.o)'; invalid r_symbolnum=1 in '../../../libcrc32c_arm64.a[2](crc32c_arm64.cc.o)'; invalid r_symbolnum=18 in '../../crypto/libbitcoin_crypto_arm_shani.a[2](sha256_arm_shani.cpp.o)'; invalid r_symbolnum=1 in '../../crypto/libbitcoin_crypto.a[15](sha3.cpp.o)'; invalid r_symbolnum=1 in '../../../libleveldb.a[37](logging.cc.o)'; invalid r_symbolnum=1 in '../../../libleveldb.a[35](hash.cc.o)'; invalid r_symbolnum=1 in '../../crypto/libbitcoin_crypto.a[10](poly1305.cpp.o)'; invalid r_symbolnum=1 in '../../crypto/libbitcoin_crypto.a[5](hex_base.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_consensus.a[11](script_error.cpp.o)'; invalid r_symbolnum=1 in '../util/libtest_util.a[12](str.cpp.o)'; invalid r_symbolnum=1 in '../../../libleveldb.a[31](crc32c.cc.o)'; invalid r_symbolnum=1 in '../../../libleveldb.a[27](bloom.cc.o)'; invalid r_symbolnum=1 in '../../libbitcoin_consensus.a[5](hash.cpp.o)'; invalid r_symbolnum=5 in '../../util/libbitcoin_util.a[29](randomenv.cpp.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[27](logging.cpp.o)'; invalid r_symbolnum=1 in '../util/libtest_util.a[4](index.cpp.o)'; invalid r_symbolnum=1 in '../util/libtest_util.a[3](coins.cpp.o)'; invalid r_symbolnum=1 in '../../../libleveldb.a[8](filename.cc.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[24](threadnames.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[47](parsing.cpp.o)'; invalid r_symbolnum=1 in '../../../libleveldb.a[2](builder.cc.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[16](serfloat.cpp.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[15](readwritefile.cpp.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[14](rbf.cpp.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[9](feefrac.cpp.o)'; invalid r_symbolnum=1 in '../../util/libbitcoin_util.a[6](chaintype.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[42](request.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[41](rawtransaction_util.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[84](torcontrol.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[79](server_util.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[30](merkleblock.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[29](key_io.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[24](deploymentinfo.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[21](compressor.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[20](url.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_common.a[16](run_command.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[68](pow.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[63](fees_args.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[55](psbt.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[54](peerman_args.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[51](miner.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[50](mempool_persist_args.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[43](database_args.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[41](connection_types.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[40](coins_view_args.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[39](coin.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[36](caches.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[34](blockmanager_args.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[31](net_processing.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[28](mempool_removal_reason.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[23](checks.cpp.o)'; invalid r_symbolnum=1 in '../../libbitcoin_node.a[22](chain.cpp.o)'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [src/test/fuzz/fuzz] Error 1
make[1]: *** [src/test/fuzz/CMakeFiles/fuzz.dir/all] Error 2
make: *** [all] Error 2

However, I am able to successfully build the fuzzer with the libfuzzer-nosan preset.

Is my llvm installation messed up somehow, in some way that prevents the sanitizers from working? Not sure how to diagnose.

I think this is an issue with latest LLVM and Apples ld, see #31049. You could brew install llvm@18 (and sub that in for however you'd got clang/clang++ available), and that will work for now, until we fix the incompatibilty.

Thanks @fanquake, yeah this looks like a duplicate issue -- closing.