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authorAlice Ryhl <aliceryhl@google.com>2025-05-01 12:16:16 +0000
committerAndrew Morton <akpm@linux-foundation.org>2025-05-31 22:46:12 -0700
commit3bf67171e98272c918a41b899070e6e86741adc8 (patch)
tree267519a6c39578e5428bcf784092f5416c99168e /scripts
parentmm: rust: make CONFIG_MMU ifdefs more narrow (diff)
downloadlinux-rng-3bf67171e98272c918a41b899070e6e86741adc8.tar.xz
linux-rng-3bf67171e98272c918a41b899070e6e86741adc8.zip
kcov: rust: add flags for KCOV with Rust
Rust code is currently not instrumented properly when KCOV is enabled. Thus, add the relevant flags to perform instrumentation correctly. This is necessary for efficient fuzzing of Rust code. The sanitizer-coverage features of LLVM have existed for long enough that they are available on any LLVM version supported by rustc, so we do not need any Kconfig feature detection. The coverage level is set to 3, as that is the level needed by trace-pc. We do not instrument `core` since when we fuzz the kernel, we are looking for bugs in the kernel, not the Rust stdlib. Link: https://lkml.kernel.org/r/20250501-rust-kcov-v2-1-b71e83e9779f@google.com Signed-off-by: Alice Ryhl <aliceryhl@google.com> Co-developed-by: Matthew Maurer <mmaurer@google.com> Signed-off-by: Matthew Maurer <mmaurer@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Aleksandr Nogikh <nogikh@google.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Cc: Andreas Hindborg <a.hindborg@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: Bill Wendling <morbo@google.com> Cc: Björn Roy Baron <bjorn3_gh@protonmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Gary Guo <gary@garyguo.net> Cc: Justin Stitt <justinstitt@google.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Trevor Gross <tmgross@umich.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/Makefile.kcov6
-rw-r--r--scripts/Makefile.lib3
2 files changed, 9 insertions, 0 deletions
diff --git a/scripts/Makefile.kcov b/scripts/Makefile.kcov
index 67e8cfe3474b..ddcc3c6dc513 100644
--- a/scripts/Makefile.kcov
+++ b/scripts/Makefile.kcov
@@ -3,4 +3,10 @@ kcov-flags-$(CONFIG_CC_HAS_SANCOV_TRACE_PC) += -fsanitize-coverage=trace-pc
kcov-flags-$(CONFIG_KCOV_ENABLE_COMPARISONS) += -fsanitize-coverage=trace-cmp
kcov-flags-$(CONFIG_GCC_PLUGIN_SANCOV) += -fplugin=$(objtree)/scripts/gcc-plugins/sancov_plugin.so
+kcov-rflags-y += -Cpasses=sancov-module
+kcov-rflags-y += -Cllvm-args=-sanitizer-coverage-level=3
+kcov-rflags-y += -Cllvm-args=-sanitizer-coverage-trace-pc
+kcov-rflags-$(CONFIG_KCOV_ENABLE_COMPARISONS) += -Cllvm-args=-sanitizer-coverage-trace-compares
+
export CFLAGS_KCOV := $(kcov-flags-y)
+export RUSTFLAGS_KCOV := $(kcov-rflags-y)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 2fe73cda0bdd..520905f19a9b 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -169,6 +169,9 @@ ifeq ($(CONFIG_KCOV),y)
_c_flags += $(if $(patsubst n%,, \
$(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \
$(CFLAGS_KCOV))
+_rust_flags += $(if $(patsubst n%,, \
+ $(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \
+ $(RUSTFLAGS_KCOV))
endif
#