Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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5.5(EOL), 10.1(EOL), 10.2(EOL), 10.3(EOL), 10.4(EOL), 10.5
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Debian GNU/Linux unstable, clang 8.0.1
Description
MemorySanitizer is a compile-time instrumentation layer in clang but not GCC. Together with AddressSanitizer mostly makes the run-time instrumentation of Valgrind redundant. It is a little more tricky to set up, because running with uninstrumented libraries will lead into false positives.
No patches are necessary since 10.5 94d0bb4dbeb28a94d1f87fdd55f4297ff3df0157 (see the commit message for instructions); cmake -DWITH_MSAN=ON is supposed to work ‘out of the box’.
This task will be kept open until all tests pass and MemorySanitizer can be enabled on CI systems.
How to instrumented libraries
These instructions are for clang-10. The script build-msan2.sh
was developed to resolve MDEV-22083 a.k.a. MDEV-26758.
mkdir /tmp/build
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cd /tmp/build
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mkdir "$HOME/msan-libs"
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CLANG=10 MSAN_LIBDIR="$HOME/msan-libs" build-msan.sh
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Note: to use different clang (tested with clang-8, clang-9, clang-11, clang-13), just replace 10 with the major version of the compiler above.
For clang-15, the procedure is a little different:
mkdir /tmp/build
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cd /tmp/build
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mkdir "$HOME/msan-libs"
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CLANG=15 MSAN_LIBDIR="$HOME/msan-libs" build-msan15.sh
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How to build MariaDB Server 10.5 or later with the instrumented libraries
cd /mariadb/10.5 |
mkdir build |
cd build |
cmake -DCMAKE_{C_COMPILER=clang,CXX_COMPILER=clang++}-10 \
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-DCMAKE_C_FLAGS='-O2 -Wno-unused-command-line-argument -fdebug-macro' \ |
-DCMAKE_CXX_FLAGS='-stdlib=libc++ -O2 -Wno-unused-command-line-argument -fdebug-macro' \ |
-DWITH_EMBEDDED_SERVER=OFF -DWITH_UNIT_TESTS=OFF -DCMAKE_BUILD_TYPE=Debug \
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-DWITH_DBUG_TRACE=OFF -DWITH_SAFEMALLOC=OFF \
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-DWITH_INNODB_{BZIP2,LZ4,LZMA,LZO,SNAPPY}=OFF \
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-DWITH_SAFEMALLOC=OFF \
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-DWITH_{ZLIB,SSL,PCRE}=bundled \
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-DHAVE_LIBAIO_H=0 -DCMAKE_DISABLE_FIND_PACKAGE_{URING,LIBAIO}=1 \
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-DWITH_MSAN=ON \
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-G Ninja ..
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ninja
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Note: -march=native -mtune=native is optional since the second fix of MDEV-20386
How to build with minimal cmake arguments
cd /mariadb/10.5 |
mkdir build |
cd build |
cmake -DCMAKE_{C_COMPILER=clang,CXX_COMPILER=clang++}-19 -DCMAKE_C_FLAGS='-O2 -march=native' \ |
-DCMAKE_CXX_FLAGS='-stdlib=libc++ -O2 -march=native' \ |
-DSECURITY_HARDENED=OFF \
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-DPLUGIN_{CONNECT,SPIDER}=NO \
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-DWITH_INNODB_{BZIP2,LZ4,LZMA,LZO,SNAPPY}=OFF \
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-DWITH_{ZLIB,SSL,PCRE}=bundled \
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-DHAVE_LIBAIO_H=0 -DCMAKE_DISABLE_FIND_PACKAGE_{URING,LIBAIO}=1 \
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-DWITH_MSAN=ON -G Ninja ..
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cmake --build .
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cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo is implied. OK, this is almost minimal. I wanted to save the trouble of building numerous compression libraries with -fsanitize=memory. Connect and Spider are disabled due to test failures that were not investigated yet. MDEV-34921 was tested in this way.
Note the -DSECURITY_HARDENED=OFF; it is enabled by default and seems to break operations like memcpy() with RelWithDebInfo but not Debug.
How to run tests
cd mysql-test
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LD_LIBRARY_PATH="$HOME"/msan-libs ./mtr main.1st
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LD_LIBRARY_PATH="$HOME"/msan-libs MSAN_OPTIONS=abort_on_error=1:poison_in_dtor=0 ./mtr --big-test --parallel=auto --force --retry=0 --skip-stack-trace --skip-core-file
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Note: It may be wise to omit MSAN_OPTIONS=abort_on_error=1 except when running code in a debugger. On some occasions, it may cause truncation of the diagnostic messages.
Note: The llvm-symbolizer in clang 14 or later will refuse to load if LD_LIBRARY_PATH includes an MSAN-instrumented libgmp.so. To get nice resolved stack traces, you must point the environment variable MSAN_SYMBOLIZER_PATH to a script like the following. The script name had better start with llvm-symbolizer- in order to avoid a warning:
#!/bin/sh
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unset LD_LIBRARY_PATH
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exec llvm-symbolizer-15 "$@"
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The MSAN_OPTIONS=poison_in_dtor=0 (to work around MDEV-30936, MDEV-30942) is an old option that was enabled by default in clang 15.
Attachments
Issue Links
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MDBF-136 MSAN - create instrumented libcrack
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