Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix KCFI failures, such as in Rust doctests, by disabling function
merging when CFI is enabled. Gary reported the LLVM bug to upstream
and it is now fixed in their mainline.
- Fix 'objtool' fallthrough warnings under the experimental
'CONFIG_RUST_INLINE_HELPERS' by passing (for the combined Rust and
helpers code) the LLVM options needed to preserve the unreachable
traps that 'rustc' normally emits.
In addition, fix 'objtool' errors when LTO is enabled on top, by
also filtering out the LTO flags (for the combined Rust and helpers
code) so that the traps are kept in place.
- Fix 'objtool' warnings by adding one more 'noreturn' function.
- Fix 'make rusttest' target when the 'rustc-dev' component is
installed and Rust >= 1.82.0, <= 1.87.0 is used.
'kernel' crate:
- 'num' module: fix soundness issue in the 'Bounded' conversion from
'bool' by restricting the conversions to unsigned 'Bounded'.
- 'jump_label' module: fix future 'make rusttest' target failures
when 'ARCH=' is set to an arch different than the host's.
- 'list' module: fix incorrect 'pop_back()' comment"
* tag 'rust-fixes-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: kbuild: disambiguate `zerocopy_derive` for `rusttest`
rust: num: restrict bool conversion to unsigned Bounded
kbuild: rust: keep Rust objects out of Clang LTO with inline helpers
kbuild: rust: preserve unreachable traps with inline helpers
rust: cfi: disable function merging if CFI is enabled
rust: jump_label: skip arch-specific asm in `testlib` builds
objtool/rust: add one more `noreturn` Rust function
rust: kernel: list: fix incorrect pop_back example comment
Pull bootconfig updates from Masami Hiramatsu:
- Support build-time command line building for embedded bootconfig
- Fix xbc_snprint_cmdline() to render descendant keys when the root has
both a value and subkeys, and treats empty subtrees correctly.
- Add build-time pipeline using tools/bootconfig -C to render the
embedded bootconfig "kernel" subtree into .init.rodata as a cmdline
string.
- Clean build-time tools/bootconfig from make clean
- Add helper to prepend embedded bootconfig cmdline into
boot_command_line early before parse_early_param()
- Wire early prepend helper in x86 setup_arch() so early_param handlers
see values from the embedded bootconfig (currently x86 only)
- Avoid duplicating "kernel" keys in setup_boot_config()
- Refactor setup_boot_config() to share bootconfig_cmdline_requested()
- Document CONFIG_CMDLINE_FROM_BOOTCONFIG usage, requirements, and
precedence
* tag 'bootconfig-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
init/main.c: use bootconfig_cmdline_requested() for the runtime opt-in
bootconfig: skip runtime kernel.* render once prepended early
x86/setup: prepend embedded bootconfig cmdline before parse_early_param
Documentation: bootconfig: document build-time cmdline rendering
bootconfig: add xbc_prepend_embedded_cmdline() helper
bootconfig: clean build-time tools/bootconfig from make clean
bootconfig: render embedded bootconfig as a kernel cmdline at build time
bootconfig: render descendant keys when xbc_snprint_cmdline() root has a value
When `CONFIG_RUST_INLINE_HELPERS` is enabled, it is possible to hit
`objtool` warnings like:
vmlinux.o: warning: objtool: _R..._4cmdq12CommandToGsp4init()
falls through to next function _R..._4core5array4iter8IntoIterRShKj3_EEEBa_()
`rustc` normally emits traps for unreachable paths. However, under
`CONFIG_RUST_INLINE_HELPERS=y`, `rustc` emits LLVM bitcode and Clang
performs final code generation after the helper bitcode is linked,
but Clang does not trap unreachable IR by default.
In turn, this means `objtool` follows compiler-generated impossible Rust
`enum` paths through alignment padding into the next function, resulting
in fallthrough warnings.
Thus pass the LLVM `trap-unreachable` option to the final Clang invocation
and suppress traps immediately after `noreturn` calls, which `objtool`
already recognizes as dead ends. The combination of both flags makes it
match `rustc`'s behavior.
Rust 1.85.0 (the minimum supported one) supports LLVM >= 18, and both
flags are available in LLVM 18.
Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1d ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust doc tests, there is a dummy `__module_firmware_test_init` function
generated by the example in `module_firmware!`'s documentation, which
just returns zero. Many other documentation examples generate functions
that produce zero. LKP test robot reports [1] a `Flags::zeroed` instance;
my local reproduction has a `Bounded::new::<0>`.
LLVM's MergeFunctionsPass incorrectly merges functions with different
KCFI types, causing `__module_firmware_test_init` to be merged into
one of the zero-returning functions. As module init is invoked via an
indirect function call, KCFI is checked and this produces a KCFI failure.
I've reported this bug to upstream LLVM [2]; in the meantime, disable
function merging if CFI is enabled. No separate treatment is needed for
CONFIG_RUST_INLINE_HELPERS, as Clang does not enable function merging
by default.
[ LLVM already has a pending PR:
https://github.com/llvm/llvm-project/pull/217665
which solves the issue. In addition, I asked upstream Rust if the
unstable `-Zmerge-functions=disabled` flag will remain around:
https://rust-lang.zulipchat.com/#narrow/channel/425075-rust-for-linux/topic/.60-Zmerge-functions.3Ddisabled.60/
and it does indeed look like that will be the case. - Miguel ]
Reported-by: kernel test robot <yi1.lai@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202608201017.100a4511-lkp@intel.com [1]
Link: https://github.com/llvm/llvm-project/issues/217629 [2]
Signed-off-by: Gary Guo <gary@garyguo.net>
Cc: stable@vger.kernel.org
Fixes: ca627e6365 ("rust: cfi: add support for CFI_CLANG with Rust")
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://patch.msgid.link/20260820135733.37121-1-gary@kernel.org
[ Fixed typos as discussed. Reworded slightly for other typos. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull livepatching updates from Petr Mladek:
- Move consistency checks to catch missing func->old_name before the
first access
- Allow to run livepatching selftests from top-level directory
* tag 'livepatching-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
kbuild: unset sub_make_done before calling kselftest build system
livepatch: Fix NULL pointer dereference in klp_find_func()
Pull Kbuild/Kconfig updates from Nicolas Schier:
"Kbuild updates:
- Use --force-group-allocation when linking modules
Have the linker resolve the COMDAT groups and place their members
as regular sections instead of possibly leaving multiple copies in
the resulting modules and unnecessary group metadata.
- UAPI header files: Canonicalize __ASSEMBLER__ / __ASSEMBLY__ mixed
use to __ASSEMBLER__
There is an ongoing effort to change __ASSEMBLY__ to __ASSEMBLER__
treewide. For consistency, UAPI headers are normalised to use
__ASSEMBLER__ only. Normalisation is done in two subsequent patches
to simplify a revert in the unexpected case of a regression report.
- link-vmlinux.sh: Improve detection of third pass requirement
- modpost: Canonicalize format of warnings and errors
- Minor changes:
- Remove srctree path from CHECK output
- Set the initial value of subdir-rustflags-y
- Remove broken and unused modules.builtin(.modinfo) targets from
the top-level Makefile
- Add symbol size for kallsyms symbols that can change size
- modpost: Prevent leak when early return no suffix .o in
read_symbols()
- scripts/config: Update usage of POSIX sed
- 'make tags': Add support for rust source files and prevent
binary files from being analysed
- Several spelling mistakes and rephrasing
Kconfig updates:
- Add Julian Braha as Kconfig reviewer
- Fix submenu rendering of negative dependencies
- Minor changes:
- merge_config.sh: Keep temp file in the output dir
- Abort rather than loop for ever on EOF"
* tag 'kbuild-7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (23 commits)
modpost: use mod_warn() and mod_error(), clean up logging
modpost: add module as parameter to modpost_log()
kconfig: fix submenu rendering of negative dependencies
kbuild: link-vmlinux.sh: improve detection of third pass requirement
kallsyms: add symbol size for kallsyms symbols that can change size
kbuild: fix modules.builtin(.modinfo) targets in the top-level Makefile
kbuild: set the initial value of subdir-rustflags-y
scripts/config: Use in-place editing (-i) in sed portably
scripts/config: Use POSIX standard ERE (-E) in sed
modpost: prevent leak when early return no suffix .o in read_symbols()
usr: Correct a spelling by changing a letter
fixdep: make gendered language gender-neutral
kconfig: fix minor typos in comments
scripts: fix spelling mistakes
kconfig: abort rather than loop for ever on EOF
scripts/tags.sh: Add support for rust source files
scripts/tags.sh: Prevent binary files appearing in cscope.files
MAINTAINERS: add Julian Braha as Kconfig reviewer
scripts: headers_install.sh: Normalize __ASSEMBLY__ to __ASSEMBLER__
scripts: headers_install.sh: Normalize __ASSEMBLER__ to __ASSEMBLY__
...
Commit 7a342e6c77 ("kbuild: move modules.builtin(.modinfo) rules to
Makefile.vmlinux_o") moved the modules.builtin(.modinfo) rules from
link-vmlinux.sh to Makefile.vmlinux_o, and added the corresponding
targets to the top-level Makefile.
Commit 39cfd5b121 ("kbuild: extract modules.builtin.modinfo from
vmlinux.unstripped") later moved these rules from Makefile.vmlinux_o to
Makefile.vmlinux, but left the corresponding targets in the top-level
Makefile unchanged.
These modules.builtin(.modinfo) targets in the top-level Makefile should
be moved alongside the vmlinux target, since they are now generated by
Makefile.vmlinux.
However, simply removing these trivial targets might be a better choice,
as it makes the Makefile cleaner and avoids the need to keep them in sync
across multiple files, reducing the chance of future mistakes.
Fixes: 39cfd5b121 ("kbuild: extract modules.builtin.modinfo from vmlinux.unstripped")
Signed-off-by: Yuntao Wang <yuntao.wang@linux.dev>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260729071737.818007-1-yuntao.wang@linux.dev
Signed-off-by: Nicolas Schier <nsc@kernel.org>
Pull Kbuild fixes from Nathan Chancellor:
- Fix regression with MO= when building out of tree kernel modules due
to incorrectly overwriting build tree's Makefile
- Avoid stripping .BTF sections from modules when building debug .rpm
packages
* tag 'kbuild-fixes-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: rpm-pkg: Preserve BTF sections in kernel modules during debuginfo stripping
kbuild: Stop modifying $(objtree)/Makefile when building oot-kmods oos
Pull rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- 'zerocopy' crates: update to v0.8.54 to fix a modpost error under
'CONFIG_CC_OPTIMIZE_FOR_SIZE=y'.
There are actually two updates in the PR: the one to v0.8.52 is
fairly large and was originally not intended for a fixes PR, but the
actual fix landed in the v0.8.54 one. Thus I included both here.
The v0.8.52 update includes two things upstream added for us:
'--cfg no_fp_fmt_parse' to avoid a local workaround, and the new
'most_traits' feature.
The good news is that, after these updates, the delta with upstream
is now trivial: only an identifier prefix change and the SPDX
parentheses.
- Fix an objtool warning by adding one more 'noreturn' function for
Rust 1.99.0 (expected 2026-10-01).
- Clean up new 'semicolon_in_expressions_from_macros' lint errors for
Rust 1.99.0 (expected 2026-10-01). The lint can be allowed, but it
will be a hard error at some point in the future anyway, so clean it
up now.
- Locally allow new 'suspicious_runtime_symbol_definitions' lint for
Rust 1.98.0 (expected 2026-08-20).
- Globally allow 'clippy::unwrap_or_default' lint since it relies on
optimizations -- under 'CONFIG_CC_OPTIMIZE_FOR_SIZE=y' it does not
work well.
'kernel' crate:
- 'time' module: fix 'Delta::as_micros_ceil()' to round negative values
correctly"
* tag 'rust-fixes-7.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: time: fix as_micros_ceil() to round correctly for negative Delta
rust: device: avoid trailing ; in printing macros
objtool/rust: add one more `noreturn` Rust function for Rust 1.99.0
rust: zerocopy: update to v0.8.54
rust: zerocopy: update to v0.8.52
rust: allow `clippy::unwrap_or_default` globally
rust: allow `suspicious_runtime_symbol_definitions` lint for Rust >= 1.98
Update output Makefile in the corresponding tree only: for out-of-source
in-tree builds update $(objtree)/Makefile, for out-of-source out-of-tree
module builds update $(KBUILD_EXTMOD_OUTPUT)/Makefile instead.
In-source builds are not affected.
Since commit c9bb03ac2c ("kbuild: reduce output spam when building out
of tree"), building out-of-tree kernel modules out-of-source (make M=...
MO=...) causes a rewrite of $(objtree)/Makefile with KBUILD_EXTMOD and
KBUILD_EXTMOD_OUTPUT being set. That is problematic:
* $(objtree)/ must not be changed in any way when building out-of-tree
modules as it breaks other uses of $(objtree).
* Setting KBUILD_EXTMOD and KBUILD_EXTMOD_OUTPUT in $(objtree)/Makefile
kills the tree for incremental builds that start right there
('make -C $(objtree)'); builds starting in $(srctree) reset
$(objtree)/Makefile to its original content.
Further, $(KBUILD_EXTMOD_OUTPUT)/Makefile was not generated any more at
all.
This commit restores the previous kbuild behaviour prior to commit
c9bb03ac2c ("kbuild: reduce output spam when building out of tree")
but leaves in-place the use of filechk for output spam reduction.
Fixes: c9bb03ac2c ("kbuild: reduce output spam when building out of tree")
Reported-by: Anish Rashinkar <rashinkar.anish@gmail.com>
Closes: https://lore.kernel.org/r/CAOESE2Q2-0KUDaM0mUo+c_F-tMaUsBZ-gpnhdoe0rmYdgnnuJQ@mail.gmail.com
Cc: stable@vger.kernel.org
Tested-by: Philipp Hahn <p.hahn@avm.de>
Reviewed-by: Philipp Hahn <p.hahn@avm.de>
Signed-off-by: Nicolas Schier <n.schier@fritz.com>
Signed-off-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260723105845.1704689-2-nsc@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Starting with rustc 1.88, the `clippy::unwrap_or_default` lint triggers
on `rust/kernel/soc.rs` if `CONFIG_CC_OPTIMIZE_FOR_SIZE=y`:
warning: use of `unwrap_or` to construct default value
--> ../rust/kernel/soc.rs:66:10
|
66 | .unwrap_or(core::ptr::null())
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `unwrap_or_default()`
This is a clippy bug [1]: the lint decides whether an expression is
equivalent to `Default::default()` by inspecting the optimized MIR of
`<*const T as Default>::default` exported by `core`, so its outcome
depends on the optimization level `core` was built with. Moreover, its
suggestion ignores our MSRV of 1.85 (`Default` for `*const T` is only
stable since Rust 1.88), so we could not apply it anyway.
Disable the lint globally rather than working around this single
occurrence; it can be re-enabled conditionally using `rustc-min-version`
once clippy is fixed.
Link: https://github.com/rust-lang/rust-clippy/issues/17379 [1]
Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://patch.msgid.link/20260708-soc_unwrap_or-v2-1-007ed724cc7b@nvidia.com
[ Moved to non-versioned group. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Specific code, such as outlined KASAN checks, may be placed in
COMDAT-deduplicated sections. When linking modules as relocatable files,
the linker by default preserves such groups, potentially leaving multiple
copies in the resulting modules and unnecessary group metadata.
Use --force-group-allocation to have the linker resolve the COMDAT groups
and place their members as regular sections. The option is available from
ld.bfd 2.29 and ld.lld 19.1.0.
Remove the workaround in arch/arm64/include/asm/module.lds.h that was added
for the same problem but limited to CONFIG_KASAN_SW_TAGS and .text.hot.
Note that this code currently has no effect anyway because all .text.hot
sections are placed in the .text output section by scripts/module.lds.S,
since commit 1ba9f89794 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and
related macros").
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260612133139.1919042-1-petr.pavlu@suse.com
[nsc: Updated patch context in arch/arm64/include/asm/module.lds.h]
Signed-off-by: Nicolas Schier <nsc@kernel.org>
The previous patch builds tools/bootconfig during 'make prepare' to
render the embedded bootconfig cmdline, but nothing removes it on
'make clean', leaving the compiled tool and its objects behind.
Wire a bootconfig_clean hook into the top-level clean target so the
compiled tool and its objects are removed by make clean, matching the
prepare-wired tools/objtool and tools/bpf/resolve_btfids.
The hook runs tools/bootconfig's Makefile via $(MAKE), which the kernel
build invokes with -rR (MAKEFLAGS += -rR). -rR drops the built-in $(RM)
variable, so the existing "$(RM) -f ..." clean recipe would expand to a
bare "-f ..." and fail. Spell the recipe with a literal "rm -f" so it
keeps working both standalone and when invoked from Kbuild.
Link: https://lore.kernel.org/all/20260626-bootconfig_using_tools-v7-4-24ab72139c29@debian.org/
Reviewed-by: Nicolas Schier <n.schier@fritz.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Add the build-time pipeline that renders the "kernel" subtree of
CONFIG_BOOT_CONFIG_EMBED_FILE into a flat cmdline string and stashes
it in .init.rodata as embedded_kernel_cmdline[]. A follow-up patch
adds the runtime helper that prepends this string to boot_command_line
during early architecture setup so parse_early_param() sees the values.
The build wires up:
tools/bootconfig -C kernel - userspace tool already shared with
lib/bootconfig.c, used here in -C mode
to render a bootconfig file to a cmdline
lib/embedded-cmdline.S - .incbin's the rendered text plus a NUL
(listed under the EXTRA BOOT CONFIG
MAINTAINERS entry)
lib/Makefile rule - runs tools/bootconfig at build time
Makefile prepare dep - ensures tools/bootconfig is built first,
same pattern as tools/objtool and
tools/bpf/resolve_btfids
Drop the test target from tools/bootconfig/Makefile's default 'all'
recipe so that hooking the binary into the kernel build does not run
test-bootconfig.sh on every prepare. The tests stay available as
'make -C tools/bootconfig test', matching the convention of
tools/objtool and tools/bpf/resolve_btfids whose 'all' targets only
build the binary.
Require BOOT_CONFIG_EMBED_FILE to be non-empty before the new option
can be enabled, otherwise tools/bootconfig -C runs against an empty
file and prints a parse error on every kernel build.
The feature gates on CONFIG_ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG, a
silent symbol arches select once they've wired the prepend call into
setup_arch(). No arch selects it in this patch, so the user-visible
CONFIG_CMDLINE_FROM_BOOTCONFIG is not yet enableable; when an arch
later opts in, the runtime behavior is added by the follow-up patches.
tools/bootconfig also installs on target systems, so its own Makefile
keeps $(CC) and stays cross-buildable as a standalone tool. The kernel
build, which runs the tool on the build host during prepare, instead
forces CC=$(HOSTCC) from a dedicated tools/bootconfig rule and clears
CROSS_COMPILE= in the sub-make. Without that clear, an LLVM=1 cross
build would inherit CROSS_COMPILE and tools/scripts/Makefile.include
would inject --target=/--sysroot= flags into the host clang invocation,
producing a target binary that fails to exec ("Exec format error").
embedded-cmdline.S places the rendered string in its own .init.rodata
subsection (.init.rodata.embed_cmdline) with the "a" (allocatable,
read-only) flag and %progbits. lib/bootconfig-data.S already places
the embedded bootconfig blob in .init.rodata with the "aw" flag
(xbc_init() rewrites separators in place, so that data must be
writable). Using a distinct subsection name avoids the ld.lld section-
type mismatch that would otherwise arise from mixing "a" and "aw"
under the same name; the linker's "*(.init.rodata .init.rodata.*)"
glob still folds both into the init image and frees them after boot.
A follow-up patch wires the build-time tools/bootconfig into the
top-level clean target.
Link: https://lore.kernel.org/all/20260626-bootconfig_using_tools-v7-3-24ab72139c29@debian.org/
Reviewed-by: Nicolas Schier <n.schier@fritz.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Pull more Kbuild updates from Nathan Chancellor:
- Link host programs with ld.lld when $(LLVM) is set to match user's
expectations that LLVM will be used exclusively during the build
process
- Fix modpost warnings from static variable name promotion that can
happen more aggressively with the recently merged distributed ThinLTO
support
- Add an optional warning for user-supplied Kconfig values that changed
after processing, such as out of range values or options that have
incorrect / missing dependencies
* tag 'kbuild-7.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kconfig: add optional warnings for changed input values
modpost: Ignore Clang LTO suffixes in symbol matching
kbuild: Use ld.lld for linking host programs when LLVM is set
Pull rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Work around a 'rustc' bug by setting the 'frame-pointer' LLVM
module flag under 'CONFIG_FRAME_POINTER'.
The upcoming Rust 1.98.0 is fixed.
- Doctests: fix incorrect replacement pattern.
'kernel' crate:
- Mark 'Debug' impl as '#[inline]'"
* tag 'rust-fixes-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: Kbuild: set frame-pointer llvm module flag for CONFIG_FRAME_POINTER
rust: doctest: fix incorrect pattern in replacement
rust: bitfield: mark `Debug` impl as `#[inline]`
Pull SPDX updates from Greg KH:
"Here is a "big" set of SPDX-like patches for 7.2-rc1. It is the
addition of the ability for the kernel build process to generate a
Software Bill of Materials (SBOM) in the SPDX format, that matches up
exactly with just the files that are actually built for the specific
kernel image generated.
To generate a sbom, after the kernel has been built, just do:
make sbom
and marvel at the JSON file that is generated...
This is needed by users for environments in which a SBOM is required
(medical, automotive, anything shipped in the EU, etc.) and cuts down
by a massive size the "naive" SBOM solution that many vendors have
done by just including _all_ of the kernel files in the resulting
document.
This result is still a giant JSON file, that I am told parses
properly, so we just have to trust that it is properly inclusive as
attempting to parse that thing by hand is impossible.
The scripts here are self-contained python scripts, no additional
libraries or tools to create the SBOM are needed, which is important
for many build systems. Overall it's just a bit over 4000 lines of
"simple" python code, the most complex part is the regex matching
lines, but those are nothing compared to what we maintain in
scripts/checkpatch.pl today...
The various parts where the tool touches the kbuild subsystem have
been acked by the kbuild maintainer, so all should be good here.
All of these patches have been in linux-next for weeks with no
reported problems"
* tag 'spdx-7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
scripts/sbom: add unit tests for SPDX-License-Identifier parsing
scripts/sbom: add unit tests for command parsers
scripts/sbom: add SPDX build graph
scripts/sbom: add SPDX source graph
scripts/sbom: add SPDX output graph
scripts/sbom: collect file metadata
scripts/sbom: add shared SPDX elements
scripts/sbom: add JSON-LD serialization
scripts/sbom: add SPDX classes
scripts/sbom: add additional dependency sources for cmd graph
scripts/sbom: add cmd graph generation
scripts/sbom: add command parsers
scripts/sbom: setup sbom logging
scripts/sbom: integrate script in make process
scripts/sbom: add documentation
Pull non-MM updates from Andrew Morton:
- "taskstats: fix TGID dead-thread stat retention" (Yiyang Chen)
Fix a taskstats TGID aggregation bug where fields added in the TGID
query path were not preserved after thread exit, and adds a kselftest
covering the regression.
- "lib/tests: string_helpers: Slight improvements" (Andy Shevchenko)
Improve lib/tests/string_helpers_kunit.c a little
- "lib/base64: decode fixes" (Josh Law)
Address minor issues in lib/base64.c
- "selftests/filelock: Make output more kselftestish" (Mark Brown)
Make the output from the ofdlocks test a bit easier for tooling to
work with. Also ignore the generated file
- "uaccess: unify inline vs outline copy_{from,to}_user() selection"
(Yury Norov)
Simplify the usercopy code by removing the selectability of inlining
copy_{from,to}_user().
- "ocfs2: validate inline xattr header consumers" (ZhengYuan Huang)
Fix a number of possible issues in the ocfs2 xattr code
- "lib and lib/cmdline enhancements" (Dmitry Antipov)
Provide additional robustness checking in the cmdline handling code
and its in-kernel testing and selftests
- "cleanup the RAID6 P/Q library" (Christoph Hellwig)
Clean up the RAID6 P/Q library to match the recent updates to the
RAID 5 XOR library and other CRC/crypto libraries
- "ocfs2: harden inode validators against forged metadata" (Michael
Bommarito)
Add three structural checks to OCFS2 dinode validation so malformed
on-disk fields are rejected before ocfs2_populate_inode() copies them
into the in-core inode
- "lib/raid: replace __get_free_pages() call with kmalloc()" (Mike
Rapoport)
Clean up the lib/raid code by using kmalloc() in more places
* tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (108 commits)
ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write
ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
lib: interval_tree_test: validate benchmark parameters
ocfs2: avoid moving extents to occupied clusters
treewide: fix transposed "sign" typos and update spelling.txt
ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec
fat: reject BPB volumes whose data area starts beyond total sectors
selftests/uevent: increase __UEVENT_BUFFER_SIZE to avoid ENOBUFS on busy systems
lib/test_firmware: allocate the configured into_buf size
fs: efs: remove unneeded debug prints
checkpatch: cuppress warnings when Reported-by: is followed by Link:
MAINTAINERS: add Alexander as a kcov reviewer
mailmap: update Alexander Sverdlin's Email addresses
fs: fat: inode: replace sprintf() with scnprintf()
ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent
ocfs2: fix race between ocfs2_control_install_private() and ocfs2_control_release()
ocfs2/dlm: require a ref for locking_state debugfs open
ocfs2: reject FITRIM ranges shorter than a cluster
ocfs2: validate fast symlink target during inode read
ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
...
Due to a rustc bug, the -Cforce-frame-pointers=y flag only emits the
frame-pointer annotation for functions, but not for the module. This
means that functions generated by the LLVM backend such as
'asan.module_ctor' do not receive the frame-pointer annotation.
This is likely to lead to broken backtraces and may also cause issues
with ftrace if these features are used with functions generated by the
LLVM backend.
Thus, use -Zllvm_module_flag to work around this rustc bug if using a
rustc without the fix.
[ The fix [1] has landed for Rust 1.98.0 (expected release on
2026-08-20). - Miguel ]
Cc: stable@vger.kernel.org # 6.12.y and later (flag not available in pinned Rust in older LTSs).
Fixes: 2f7ab1267d ("Kbuild: add Rust support")
Link: https://github.com/rust-lang/rust/pull/156980 [1]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260616-frame-ptr-fix-v1-1-dc6b29a631d9@google.com
[ - Adjusted Cc: stable@ as discussed.
- Added comment with link to the PR, similar to what we did in commit
ac35b5580a ("rust: arm64: set uwtable llvm module flag for
CONFIG_UNWIND_TABLES").
- Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull devicetree updates from Rob Herring:
"DT core:
- Add support for handling multiple cells in "iommu-map" entries
- Support only 1 entry in /reserved-memory "reg" entries. Support for
more than 1 entry has been broken
- Fix a UAF on alloc_reserved_mem_array() failure
- Make "ibm,phandle" handling logic specific to PPC
- Use memcpy() instead of strcpy() for known length strings
- Ensure __of_find_n_match_cpu_property() handles malformed "reg"
entries
- Add various checks that expected strings are strings before
accessing them
- Drop redundant memset() when unflattening DT
DT bindings:
- Add a DTS style checker. Currently hooked up to dt_binding_check to
check examples
- Convert st,nomadik platform, ti,omap-dmm, and ti,irq-crossbar
bindings to DT schema
- Add Apple System Management Controller hwmon, Qualcomm Hamoa
Embedded Controller, Qualcomm IPQ6018 PWM controller, fsl,mc1323,
Samsung SOFEF01-M DDIC panel, Freescale i.MX53 Television Encoder,
Samsung S2M series PMIC extcon, and MT6365 PMIC AuxADC schemas
- Extend bindings for QCom Maili and Nord PDC, QCom Hali fastrpc,
qcom,eliza-imem, qcom,oryon-1-5 CPU, and MT6365 Keys
- Consolidate "sram" property definitions
- Fix constraints on "nvmem" properties which only contain phandles
and no arg cells
- Another pass of fixing "phandle-array" constraints
- Add Gira vendor prefix"
* tag 'devicetree-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (50 commits)
dt-bindings: interrupt-controller: qcom,pdc: Add Maili compatible string
dt-bindings: interrupt-controller: ti,irq-crossbar: Convert to DT schema
dt-bindings: vendor-prefixes: add Gira
dt-bindings: embedded-controller: Add Qualcomm reference device EC description
dt-bindings: pwm: add IPQ6018 binding
dt-bindings: hwmon: Add Apple System Management Controller hwmon schema
docs: dt: writing-schema: Clarify what is required in a schema
of: Respect #{iommu,msi}-cells in maps
of: Factor arguments passed to of_map_id() into a struct
of: Add convenience wrappers for of_map_id()
of: reserved_mem: zero total_reserved_mem_cnt if no valid /reserved-memory entry
of: reserved_mem: handle NULL name in of_reserved_mem_lookup()
dt-bindings: cache: l2c2x0: Add missing power-domains
dt-bindings: interrupt-controller: renesas,r9a09g077-icu: Fix reg size in example
dt-bindings: nvmem: consumer: Make 'nvmem' an array of one-item entries
drivers/of/overlay: Use memcpy() to copy known length strings
dt-bindings: add self-test fixtures for style checker
dt-bindings: wire style checker into dt_binding_check
scripts/jobserver-exec: propagate child exit status
dt-bindings: add DTS style checker
...
Pull slab updates from Vlastimil Babka:
- Support for "allocation tokens" (currently available in Clang 22+)
for smarter partitioning of kmalloc caches based on the allocated
object type, which can be enabled instead of the "random"
per-caller-address-hash partitioning.
It should be able to deterministically separate types containing a
pointer from those that do not (Marco Elver)
- Improvements and simplification of the kmem_cache_alloc_bulk() and
mempool_alloc_bulk() API. This includes adaptation of callers
(Christoph Hellwig)
- Performance improvements and cleanups related mostly to sheaves
refill (Hao Li, Shengming Hu, Vlastimil Babka)
- Several fixups for the slabinfo tool (Xuewen Wang)
* tag 'slab-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm/slab: do not limit zeroing to orig_size when only red zoning is enabled
mm/slub: preserve original size in _kmalloc_nolock_noprof retry path
mm: simplify the mempool_alloc_bulk API
mm/slab: improve kmem_cache_alloc_bulk
mm/slub: detach and reattach partial slabs in batch
mm/slub: introduce helpers for node partial slab state
mm/slub: use empty sheaf helpers for oversized sheaves
tools/mm/slabinfo: remove redundant slab->partial assignment
tools/mm/slabinfo: remove dead assignment in get_obj_and_str()
tools/mm/slabinfo: Fix trace disable logic inversion
MAINTAINERS: add slab-related scripts and tools to SLAB ALLOCATOR
mm/slub: fix typo in sheaves comment
mm, slab: simplify returning slab in __refill_objects_node()
mm, slab: add an optimistic __slab_try_return_freelist()
slab: fix kernel-docs for mm-api
slab: improve KMALLOC_PARTITION_RANDOM randomness
slab: support for compiler-assisted type-based slab cache partitioning
mm/slub: defer freelist construction until after bulk allocation from a new slab
Pull Rust updates from Miguel Ojeda:
"This one is big due to the vendoring of the `zerocopy` library, which
allows us to replace a bunch of `unsafe` code dealing with conversions
between byte sequences and other types with safe alternatives. More
details on that below (and in its merge commit).
Toolchain and infrastructure:
- Introduce support for the 'zerocopy' library [1][2]:
Fast, safe, compile error. Pick two.
Zerocopy makes zero-cost memory manipulation effortless. We write
`unsafe` so you don't have to.
It essentially provides derivable traits (e.g. 'FromBytes') and
macros (e.g. 'transmute!') for safely converting between byte
sequences and other types. Having such support allows us to remove
some 'unsafe' code.
It is among the most downloaded Rust crates and it is also used by
the Rust compiler itself.
It is licensed under "BSD-2-Clause OR Apache-2.0 OR MIT".
The crates are imported essentially as-is (only +2/-3 lines needed
to be adapted), plus SPDX identifiers. Upstream has since added the
SPDX identifiers as well as one of the tweaks at my request, thus
reducing our future diffs on updates -- I keep the details in one
of our usual live lists [3].
In total, it is about ~39k lines added, ~32k without counting
'benches/' which are just for documentation purposes.
The series includes a few Kbuild and rust-analyzer improvements and
an example patch using it in Nova, removing one 'unsafe impl'.
I checked that the codegen of an isolated example function (similar
to the Nova patch on top) is essentially identical. It also turns
out that (for that particular case) the 'zerocopy' version, even
with 'debug-assertions' enabled, has no remaining panics, unlike a
few in the current code (since the compiler can prove the remaining
'ub_checks' statically).
So their "fast, safe" does indeed check out -- at least in that
case.
- Support AutoFDO. This allows Rust code to be profiled and optimized
based on the profile. Tested with Rust Binder: ~13% slower without
AutoFDO in the binderAddInts benchmark (using an app-launch
benchmark for the profile).
- Support Software Tag-Based KASAN.
In addition, fix KASAN Kconfig by requiring Clang.
- Add Kconfig options for each existing Rust KUnit test suite, such
as 'CONFIG_RUST_BITMAP_KUNIT_TEST'.
They are placed within a new menu, 'CONFIG_RUST_KUNIT_TESTS', in
the new 'rust/kernel/Kconfig.test' file.
- Support the upcoming Rust 1.98.0 release (expected 2026-08-20):
lint cleanups and an unstable flag rename.
- Disable 'rustdoc' documentation inlining for all prelude items,
which bloats the generated documentation.
- Ignore (in Git) and clean (in Kbuild) the (rarely) 'rustc'-generated
'*.long-type-*.txt' files.
'kernel' crate:
- Add new 'bitfield' module with the 'bitfield!' macro (extracted
from the existing 'register!' one), which declares integer types
that are split into distinct bit fields of arbitrary length.
Each field is a 'Bounded' of the appropriate bit width (ensuring
values are properly validated and avoiding implicit data loss) and
gets several generated getters and setters (infallible, 'const' and
fallible) as well as associated constants ('_MASK', '_SHIFT' and
'_RANGE'). It also supports fields that can be converted from/to
custom types, either fallibly ('?=>') or infallibly ('=>').
For instance:
bitfield! {
struct Rgb(u16) {
15:11 blue;
10:5 green;
4:0 red;
}
}
// Compile-time checks.
let color = Rgb::zeroed().with_const_green::<0x1f>();
assert_eq!(color.green(), 0x1f);
assert_eq!(color.into_raw(), 0x1f << Rgb::GREEN_SHIFT);
Add as well documentation and a test suite for it, as usual; and
update the 'register!' macro to use it.
It will be maintained by Alexandre Courbot (with Yury Norov as
reviewer) under a new 'MAINTAINERS' entry: 'RUST [BITFIELD]'.
- 'ptr' module: rework index projection syntax into keyworded syntax
and introduce panicking variant.
The keyword syntax ('build:', 'try:', 'panic:') is more explicit
and paves the way of perhaps adding more flavors in the future,
e.g. an 'unsafe' index projection.
For instance, projections now look like this:
fn f(p: *const [u8; 32]) -> Result {
// Ok, within bounds, checked at build time.
project!(p, [build: 1]);
// Build error.
project!(p, [build: 128]);
// `OutOfBound` runtime error (convertible to `ERANGE`).
project!(p, [try: 128]);
// Runtime panic.
project!(p, [panic: 128]);
Ok(())
}
Update as well the users, which now look like e.g.
// Pointer to the first entry of the GSP message queue.
let data = project!(self.0.as_ptr(), .gspq.msgq.data[build: 0]);
- 'build_assert' module: make the module the home of its macros
instead of rendering them twice.
- 'sync' module: add 'UniqueArc::as_ptr()' associated function.
- 'alloc' module:
- Fix the 'Vec::reserve()' doctest to properly account for the
existing vector length in the capacity assertion.
- Fix an incorrect operator in the 'Vec::extend_with()' 'SAFETY'
comment; add a doc test demonstrating basic usage and the
zero-length case.
- Clean imports across several modules to follow the "kernel
vertical" import style in order to minimize conflicts.
'pin-init' crate:
- User visible changes:
- Do not generate 'non_snake_case' warnings for identifiers that
are syntactically just users of a field name. This would allow
all '#[allow(non_snake_case)]' in nova-core to be removed,
which Gary will send to the nova tree next cycle.
- Filter non-cfg attributes out properly in derived structs. This
improves pin-init compatibility with other derive macros.
- Insert projection types' where clause properly.
- Other changes:
- Bump MSRV to 1.82, plus associated cleanups.
- Overhaul how init slots are projected. The new approach is
easier to justify with safety comments.
- Mark more functions as inline, which should help mitigate the
super-long symbol name issue due to lack of inlining.
rust-analyzer:
- Support '--envs' for passing env vars for crates like 'zerocopy'.
'MAINTAINERS':
- Add the following reviewers to the 'RUST' entry:
- Daniel Almeida
- Tamir Duberstein
- Alexandre Courbot
- Onur Özkan
They have been involved in the Rust for Linux project for about 7
collective years and bring expertise across several domains, which
will be very useful to have around in the future.
Thanks everyone for stepping up!
And some other fixes, cleanups and improvements"
Link: https://github.com/google/zerocopy [1]
Link: https://docs.rs/zerocopy [2]
Link: https://github.com/Rust-for-Linux/linux/issues/1239 [3]
* tag 'rust-7.2' of gitolite.kernel.org:pub/scm/linux/kernel/git/ojeda/linux: (86 commits)
MAINTAINERS: add Onur Özkan as Rust reviewer
MAINTAINERS: add Alexandre Courbot as Rust reviewer
MAINTAINERS: add Tamir Duberstein as Rust reviewer
MAINTAINERS: add Daniel Almeida as Rust reviewer
kbuild: rust: clean `zerocopy-derive` in `mrproper`
rust: make `build_assert` module the home of related macros
rust: str: clean unused import for Rust >= 1.98
rust: str: use the "kernel vertical" imports style
rust: aref: use the "kernel vertical" imports style
rust: page: use the "kernel vertical" imports style
gpu: nova-core: firmware: parse `FalconUCodeDescV2` via `zerocopy`
rust: prelude: add `zerocopy{,_derive}::FromBytes`
rust: zerocopy-derive: enable support in kbuild
rust: zerocopy-derive: add `README.md`
rust: zerocopy-derive: avoid generating non-ASCII identifiers
rust: zerocopy-derive: add SPDX License Identifiers
rust: zerocopy-derive: import crate
rust: zerocopy: enable support in kbuild
rust: zerocopy: add `README.md`
rust: zerocopy: remove float `Display` support
...
Pull Kbuild / Kconfig updates from Nathan Chancellor:
"Kbuild:
- Remove broken module linking exclusion for BTF
- Add documentation around how offset header files work
- Include unstripped vDSO libraries in pacman packages
- Bump minimum version of LLVM for building the kernel to 17.0.1 and
clean up unnecessary workarounds
- Use a context manager in run-clang-tools
- Add dist macro value if present to release tag for RPM packages
- Detect and report truncated buf_printf() output in modpost
- Add __llvm_covfun and __llvm_covmap to section whitelist in modpost
- Support Clang's distributed ThinLTO mode
- Remove architecture specific configurations for AutoFDO and
Propeller to ease individual architecture maintenance
Kconfig:
- Add kconfig-sym-check target to look for dangling Kconfig symbol
references and invalid tristate literal values
- Harden against potential NULL pointer dereference
- Fix typo in Kconfig test comment"
* tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (31 commits)
kconfig: tests: fix typo in comment
kconfig: Remove the architecture specific config for Propeller
kconfig: Remove the architecture specific config for AutoFDO
modpost: Add __llvm_covfun and __llvm_covmap to section_white_list
kconfig: add kconfig-sym-check static checker
kbuild: Remove unnecessary 'T' modifier in cmd_ar_builtin_fixup
kbuild: distributed build support for Clang ThinLTO
kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
scripts: modpost: detect and report truncated buf_printf() output
kbuild: rpm-pkg: append %{?dist} macro to Release tag
run-clang-tools: run multiprocessing.Pool as context manager
compiler-clang.h: Drop explicit version number from "all" diagnostic macro
compiler-clang.h: Remove __cleanup -Wunused-variable workaround
kbuild: Remove check for broken scoping with clang < 17 in CC_HAS_ASM_GOTO_OUTPUT
x86/entry/vdso32: Remove conditional omission of '.cfi_offset eflags'
x86/module: Revert "Deal with GOT based stack cookie load on Clang < 17"
x86/build: Drop unnecessary '-ffreestanding' addition to KBUILD_CFLAGS
scripts/Makefile.warn: Drop -Wformat handling for clang < 16
riscv: Drop tautological condition from TOOLCHAIN_NEEDS_OLD_ISA_SPEC
riscv: Remove tautological condition from selection of ARCH_SUPPORTS_CFI
...
Currently, host programs are linked with HOSTCC using the toolchain's
default linker. This can result in confusing behavior when using the
LLVM Kbuild variable (which states that the user would like to build
with the LLVM toolchain instead of the GNU one), as clang's default
linker is ld for most platforms, not ld.lld. The documentation mentions
HOSTLD=ld.lld is set but this variable is not used by Kbuild proper,
only within some tools/ projects. Kbuild provides the HOSTLDFLAGS
variable, which allow users to provide the '-fuse-ld' or '--ld-path'
flags to customize what linker is used, but this is not super obvious to
folks not familiar with Kbuild.
If the user has not customized the linker already using one of these
flags, default to ld.lld when using the LLVM variable, which is more in
line with user expectations when using that variable.
Closes: https://github.com/ClangBuiltLinux/linux/issues/2167
Link: https://patch.msgid.link/20260610-kbuild-use-lld-for-linking-hostprogs-v1-1-70396fe42ee3@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
With all the new files in place and ready from the new crate, enable
the support for it in the build system.
In addition, skip formatting for this vendored crate.
Finally, there are no generated symbols expected from `zerocopy`, thus
skip adding the `exports` generation.
Link: https://patch.msgid.link/20260608141439.182634-13-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix 'rustc-option' (the Makefile one) when cross-compiling that
leads to build or boot failures in certain configs
- Work around a Rust compiler bug (already fixed for Rust 1.98.0)
thats lead to boot failures in certain configs due to missing
'uwtable' LLVM module flags
- Support a Rust compiler change (starting with Rust 1.98.0) in the
unstable target specification JSON files
- Forbid Rust + arm + KASAN configs, which do not build
'kernel' crate:
- Fix NOMMU build by adding a missing helper"
* tag 'rust-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: x86: support Rust >= 1.98.0 target spec
rust: arm64: set uwtable llvm module flag for CONFIG_UNWIND_TABLES
rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds
rust: kasan/kbuild: fix rustc-option when cross-compiling
ARM: Do not select HAVE_RUST when KASAN is enabled
Add 'make kconfig-sym-check', a static checker that finds Kconfig
symbols referenced in expressions (select, depends on, default, etc.)
but never defined via config/menuconfig anywhere in the tree. New
dangling symbols are reported as errors (exit 1) unless they are
listed in an exclusion file, e.g.
KCONFIG_SYM_CHECK_EXCLUDES=sym-check-excludes make kconfig-sym-check
The exclusion file lists one symbol per line; blank lines and lines
starting with '#' are ignored.
The checker also warns about uppercase N/Y/M used as tristate literal
values following the same logic as checkpatch.
This new static checker is the script used for [1] with a few
improvements to avoid some false positives.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216748 [1]
Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Julian Braha <julianbraha@gmail.com>
Tested-by: Nicolas Schier <nsc@kernel.org>
Acked-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260527142703.107110-1-andrew.jones@linux.dev
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
When rustc prints an error containing a long type that doesn't fit
in a line, it will write the whole thing in a .txt file -- see commit
420dd187e1 (".gitignore: ignore rustc long type txt files") for more
details.
These files are purely compiler artifacts and are not created
intentionally by the build system.
Thus add them to the `clean` target to stop them from cluttering up the
source tree.
Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1236
Signed-off-by: Joel Kamminga <contact@jkam.dev>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260530184944.10459-1-contact@jkam.dev
[ Reworded and linked to the previous related commit. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Add distributed ThinLTO build support for the Linux kernel.
This new mode offers several advantages: (1) Increased
flexibility in handling user-specified build options.
(2) Improved user-friendliness for developers. (3) Greater
convenience for integrating with objtool and livepatch.
Note that "distributed" in this context refers to a term
that differentiates in-process ThinLTO builds by invoking
backend compilation through the linker, not necessarily
building in distributed environments.
Distributed ThinLTO is enabled via the
`CONFIG_LTO_CLANG_THIN_DIST` Kconfig option. For example:
> make LLVM=1 defconfig
> scripts/config -e LTO_CLANG_THIN_DIST
> make LLVM=1 oldconfig
> make LLVM=1 vmlinux -j <..>
The build flow proceeds in four stages:
1. Perform FE compilation, mirroring the in-process ThinLTO mode.
2. Thin-link the generated IR files and object files.
3. Find all IR files and perform BE compilation, using the flags
stored in the .*.o.cmd files.
4. Link the BE results to generate the final vmlinux.o.
NOTE: This patch currently implements the build for the main kernel
image (vmlinux) only. Kernel module support is planned for a
subsequent patch.
Tested on the following arch: x86, arm64, loongarch, and
riscv.
The earlier implementation details can be found here:
https://discourse.llvm.org/t/rfc-distributed-thinlto-build-for-kernel/85934
Signed-off-by: Rong Xu <xur@google.com>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Piotr Gorski <piotrgorski@cachyos.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260529185347.2418373-4-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
GCC's GCOV instrumentation can merge global branch counters with loop
induction variables as an optimization. In inflate_fast(), the inner copy
loops get transformed so that the GCOV counter value is loaded multiple
times to compute the loop base address, start index, and end bound. Since
GCOV counters are global (not per-CPU), concurrent execution on different
CPUs causes the counter to change between loads, producing inconsistent
values and out-of-bounds memory writes.
The crash manifests during IPComp (IP Payload Compression) processing when
inflate_fast() runs concurrently on multiple CPUs:
BUG: unable to handle page fault for address: ffffd0a3c0902ffa
RIP: inflate_fast+1431
Call Trace:
zlib_inflate
__deflate_decompress
crypto_comp_decompress
ipcomp_decompress [xfrm_ipcomp]
ipcomp_input [xfrm_ipcomp]
xfrm_input
At the crash point, the compiler generated three loads from the same
global GCOV counter (__gcov0.inflate_fast+216) to compute base, start, and
end for an indexed loop. Another CPU modified the counter between loads,
making the values inconsistent - the write went 3.4 MB past a 65 KB
buffer.
Add -fprofile-update=prefer-atomic to CFLAGS_GCOV at the global level in
the top-level Makefile, guarded by a try-run compile test. The test
compiles a minimal program with and without -fprofile-update=prefer-atomic
using the full KBUILD_CFLAGS, then compares undefined symbols in the
resulting object files. If prefer-atomic introduces new undefined
references (such as __atomic_fetch_add_8 on i386 or __aarch64_ldadd8_relax
on arm64 with outline-atomics), the flag is not added -- the kernel does
not link against libatomic.
On architectures where GCC inlines 64-bit atomic counter updates (x86_64,
s390, ...) the test passes and the flag is enabled, preventing the
compiler from merging counters with loop induction variables and fixing
the observed concurrent-access crash.
On architectures where the flag would introduce libatomic dependencies, it
is silently omitted and behaviour is no worse than before this patch.
Move the CFLAGS_GCOV block from its original position (before the arch
Makefile include) to after the core KBUILD_CFLAGS assignments but before
the scripts/Makefile.gcc-plugins include. This placement ensures the
try-run test sees arch-specific flags (-m32, -march=,
-mno-outline-atomics) while avoiding GCC plugin flags (-fplugin=) that
would break the test on clean builds when plugin shared objects do not yet
exist.
Link: https://lore.kernel.org/20260511105052.417187-2-khorenko@virtuozzo.com
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The Makefile version of rustc-option currently checks whether the option
exists for the host target instead of the target actually being compiled
for. It was done this way in commit 46e24a545c ("rust: kasan/kbuild:
fix missing flags on first build") to avoid a circular dependency on
target.json. However, because of this, rustc-option currently does not
function when cross-compiling from x86_64 to aarch64 if
CONFIG_SHADOW_CALL_STACK is enabled. This is because KBUILD_RUSTFLAGS
contains -Zfixed-x18 under this configuration. Since that flag does not
exist on the host target, rustc-option runs into a compilation failure
every time, leading to all flags being rejected as unsupported.
To fix this, update rustc-option to pass a --target parameter so that
the host target is not used. For targets using target.json, use a
built-in target that is as close as possible to the target created with
target.json to avoid the circular dependency on target.json.
One scenario where this causes a boot failure:
* Cross-compiled from x86_64 to aarch64.
* With CONFIG_SHADOW_CALL_STACK=y
* With CONFIG_KASAN_SW_TAGS=y
* With CONFIG_KASAN_INLINE=n
Then the resulting kernel image will fail to boot when it first calls
into Rust code with a crash along the lines of "Unable to handle kernel
paging request at virtual address 0ffffffc08541796". This is because the
call threshold is not specified, so rustc will inline kasan operations,
but the kasan shadow offset is not specified, which leads to the inlined
kasan instructions being incorrect.
Note that the -Zsanitizer=kernel-hwaddress parameter itself does not
lead to a rustc-option failure despite being aarch64-specific because
RUSTFLAGS_KASAN has not yet been added to KBUILD_RUSTFLAGS when
rustc-option is evaluated by the kasan Makefile.
Cc: stable@vger.kernel.org
Fixes: 46e24a545c ("rust: kasan/kbuild: fix missing flags on first build")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260507-rustc-option-cross-v2-1-2f650a49c2b5@google.com
[ Edited slightly:
- Reset variable to avoid using the environment.
- Use a simply expanded variable flavor for simplicity.
- Export variable so that behavior in sub-`make`s is consistent.
This matches other variables. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Linus Torvalds