From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- tools/testing/kunit/configs/all_tests.config | 62 +++++++++++++++++++++++++ tools/testing/kunit/configs/arch_uml.config | 7 +++ tools/testing/kunit/configs/coverage_uml.config | 11 +++++ tools/testing/kunit/configs/default.config | 3 ++ 4 files changed, 83 insertions(+) create mode 100644 tools/testing/kunit/configs/all_tests.config create mode 100644 tools/testing/kunit/configs/arch_uml.config create mode 100644 tools/testing/kunit/configs/coverage_uml.config create mode 100644 tools/testing/kunit/configs/default.config (limited to 'tools/testing/kunit/configs') diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config new file mode 100644 index 000000000..6825c2e85 --- /dev/null +++ b/tools/testing/kunit/configs/all_tests.config @@ -0,0 +1,62 @@ +# This config enables as many tests as possible under UML. +# It is intended for use in continuous integration systems and similar for +# automated testing of as much as possible. +# The config is manually maintained, though it uses KUNIT_ALL_TESTS=y to enable +# any tests whose dependencies are already satisfied. Please feel free to add +# more options if they any new tests. + +CONFIG_KUNIT=y +CONFIG_KUNIT_EXAMPLE_TEST=y +CONFIG_KUNIT_ALL_TESTS=y + +CONFIG_FORTIFY_SOURCE=y + +CONFIG_IIO=y + +CONFIG_EXT4_FS=y + +CONFIG_MSDOS_FS=y +CONFIG_VFAT_FS=y + +CONFIG_PCI=y +CONFIG_USB4=y +CONFIG_I2C=y +CONFIG_GPIOLIB=y + +CONFIG_NET=y +CONFIG_MCTP=y +CONFIG_MCTP_FLOWS=y + +CONFIG_INET=y +CONFIG_MPTCP=y + +CONFIG_NETDEVICES=y +CONFIG_WLAN=y +CONFIG_CFG80211=y +CONFIG_MAC80211=y +CONFIG_WLAN_VENDOR_INTEL=y +CONFIG_IWLWIFI=y + +CONFIG_DAMON=y +CONFIG_DAMON_VADDR=y +CONFIG_DAMON_PADDR=y + +CONFIG_REGMAP_BUILD=y + +CONFIG_AUDIT=y + +CONFIG_CRYPTO_LIB_ENABLE_ALL_FOR_KUNIT=y + +CONFIG_PRIME_NUMBERS=y + +CONFIG_CRC_ENABLE_ALL_FOR_KUNIT=y + +CONFIG_SECURITY=y +CONFIG_SECURITY_APPARMOR=y +CONFIG_SECURITY_LANDLOCK=y + +CONFIG_SOUND=y +CONFIG_SND=y +CONFIG_SND_SOC=y +CONFIG_SND_SOC_TOPOLOGY_BUILD=y +CONFIG_SND_SOC_CS35L56_I2C=y diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config new file mode 100644 index 000000000..28edf816a --- /dev/null +++ b/tools/testing/kunit/configs/arch_uml.config @@ -0,0 +1,7 @@ +# Config options which are added to UML builds by default + +# Enable pci, as a lot of tests require it. +CONFIG_KUNIT_UML_PCI=y + +# Enable FORTIFY_SOURCE for wider checking. +CONFIG_FORTIFY_SOURCE=y diff --git a/tools/testing/kunit/configs/coverage_uml.config b/tools/testing/kunit/configs/coverage_uml.config new file mode 100644 index 000000000..bacb77664 --- /dev/null +++ b/tools/testing/kunit/configs/coverage_uml.config @@ -0,0 +1,11 @@ +# This config fragment enables coverage on UML, which is different from the +# normal gcov used in other arches (no debugfs). +# Example usage: +# ./tools/testing/kunit/kunit.py run \ +# --kunitconfig=tools/testing/kunit/configs/all_tests_uml.config \ +# --kunitconfig=tools/testing/kunit/configs/coverage_uml.config + +CONFIG_DEBUG_KERNEL=y +CONFIG_DEBUG_INFO=y +CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y +CONFIG_GCOV=y diff --git a/tools/testing/kunit/configs/default.config b/tools/testing/kunit/configs/default.config new file mode 100644 index 000000000..e67af7b9f --- /dev/null +++ b/tools/testing/kunit/configs/default.config @@ -0,0 +1,3 @@ +CONFIG_KUNIT=y +CONFIG_KUNIT_EXAMPLE_TEST=y +CONFIG_KUNIT_ALL_TESTS=y -- cgit v1.3.1