GCC version 11 recently implemented all requirements to correctly support KCSAN:
1. Correct no_sanitize-attribute inlining behaviour: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4089df8ef4a63126b0774c39b6638845244c20d2 2. --param=tsan-distinguish-volatile https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ab2789ec507a94f1a75a6534bca51c7b39037ce0 3. --param=tsan-instrument-func-entry-exit https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=06712fc68dc9843d9af7c7ac10047f49d305ad76 Therefore, we can re-enable GCC for KCSAN, and document the new compiler requirements. Signed-off-by: Marco Elver <el...@google.com> Cc: Martin Liska <mli...@suse.cz> --- For anyone interested to try it out before GCC 11 is released, I'd recommend building a stable GCC 10 with the patches applied: git clone git://gcc.gnu.org/git/gcc.git && cd gcc git checkout -b gcc-10-for-kcsan releases/gcc-10.1.0 git cherry-pick \ 4089df8ef4a63126b0774c39b6638845244c20d2 \ ab2789ec507a94f1a75a6534bca51c7b39037ce0 \ 06712fc68dc9843d9af7c7ac10047f49d305ad76 ./configure --prefix <your-prefix> --enable-languages=c,c++ make -j$(nproc) && make install --- Documentation/dev-tools/kcsan.rst | 3 ++- lib/Kconfig.kcsan | 3 ++- scripts/Makefile.kcsan | 2 +- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/Documentation/dev-tools/kcsan.rst b/Documentation/dev-tools/kcsan.rst index ce4bbd918648..8fa0dd6c8614 100644 --- a/Documentation/dev-tools/kcsan.rst +++ b/Documentation/dev-tools/kcsan.rst @@ -8,7 +8,8 @@ approach to detect races. KCSAN's primary purpose is to detect `data races`_. Usage ----- -KCSAN requires Clang version 11 or later. +KCSAN is supported by both GCC and Clang. With GCC we require version 11 or +later, and with Clang also require version 11 or later. To enable KCSAN configure the kernel with:: diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan index 3f3b5bca7a8f..3d282d51849b 100644 --- a/lib/Kconfig.kcsan +++ b/lib/Kconfig.kcsan @@ -4,7 +4,8 @@ config HAVE_ARCH_KCSAN bool config HAVE_KCSAN_COMPILER - def_bool CC_IS_CLANG && $(cc-option,-fsanitize=thread -mllvm -tsan-distinguish-volatile=1) + def_bool (CC_IS_CLANG && $(cc-option,-fsanitize=thread -mllvm -tsan-distinguish-volatile=1)) || \ + (CC_IS_GCC && $(cc-option,-fsanitize=thread --param tsan-distinguish-volatile=1)) help For the list of compilers that support KCSAN, please see <file:Documentation/dev-tools/kcsan.rst>. diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan index bd4da1af5953..dd66206f4578 100644 --- a/scripts/Makefile.kcsan +++ b/scripts/Makefile.kcsan @@ -6,7 +6,7 @@ ifdef CONFIG_KCSAN ifdef CONFIG_CC_IS_CLANG cc-param = -mllvm -$(1) else -cc-param = --param -$(1) +cc-param = --param $(1) endif # Keep most options here optional, to allow enabling more compilers if absence -- 2.27.0.290.gba653c62da-goog
