This variable was removed upstream in commit bad6beb2c0 ("kbuild:
remove extmod_prefix, MODORDER, MODULES_NSDEPS variables"). However, it
was mistakenly kept during a merge conflict resolution. Drop it!
Fixes: f9d4616300 ("Merge 'Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild'")
Change-Id: I8e5b6c10ab82b8ccc16a1bb575b96c3f68f1f9e5
Signed-off-by: Carlos Llamas <cmllamas@google.com>
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
...
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
Modpost emits hundreds of warnings when using Clang to build for ARCH=um
and CONFIG_GCOV=y. e.g.:
vmlinux (__llvm_covfun): unexpected non-allocatable section.
Did you forget to use "ax"/"aw" in a .S file?
Note that for example <linux/init.h> contains
section definitions for use in .S files.
For example, when we use LLVM for a kunit user mode build with coverage:
python3 tools/testing/kunit/kunit.py build --make_options LLVM=1 \
--kunitconfig=tools/testing/kunit/configs/default.config \
--kunitconfig=tools/testing/kunit/configs/coverage_uml.config
The behaviour occurs when building the kernel for ARCH=um with code
coverage enabled. The warnings come from modpost's check_sec_ref
function, which ensures no sections reference others that will be
discarded. covfun and covmap sections must reference __init and __exit
sections to collect coverage data, triggering the modpost warning.
To suppress these warnings, these section names have been added to
modpost's whitelist. This is unlikely to suppress legitimate warnings as
Clang will only insert these sections when building with coverage, and
can be assumed to manage these references safely.
Signed-off-by: James Lee <james@codeconstruct.com.au>
Link: https://patch.msgid.link/20260604-dev-coverage-patch-v1-1-9f9368253cb4@codeconstruct.com.au
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
The err_repeated_inc test was added with an expected stderr fixture
that does not match the diagnostic printed by kconfig.
Running "make testconfig" currently fails in that test even though the
parser reports the duplicated include correctly:
[stderr]
Kconfig.inc1:4: error: repeated inclusion of Kconfig.inc3
Kconfig.inc2:3: note: location of first inclusion of Kconfig.inc3
The fixture expects "Repeated" and "Location" with capital letters, but
the diagnostic emitted by scripts/kconfig/util.c uses lowercase words.
Update the fixture to match the real message.
Fixes: 102d712ded ("kconfig: Error out on duplicated kconfig inclusion")
Signed-off-by: Zhou Yuhang <zhouyuhang@kylinos.cn>
Tested-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260520070800.2265479-1-zhouyuhang1010@163.com
Signed-off-by: Nicolas Schier <nsc@kernel.org>
When the unused exports whitelist is provided, the symbol protection bit
is set for symbols not present in the unused exports whitelist.
The flag will be used in the following commit to prevent unsigned
modules from the using symbols other than those explicitly declared by
the such modules ahead of time.
Bug: 519119852
Change-Id: Ibddd628a8b1463397cc95d3d8f556b9bc82bf623
Signed-off-by: Siddharth Nayyar <sidnayyar@google.com>
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>
In cmd_ar_builtin_fixup, the 'T' modifier was added to '$(AR) mPi' to
work around a bug in llvm-ar that caused thin archives to be silently
converted to full archives [1]. Since commit 20c0989283 ("kbuild: Bump
minimum version of LLVM for building the kernel to 15.0.0"), all
supported versions of llvm-ar have this issue fixed, so the 'T' modifier
and comment can be removed.
Link: https://github.com/llvm/llvm-project/commit/d17c54d17de22d2961a04163f3dbc8e973de89b8 [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Starting with Rust 1.98.0 (expected 2026-08-20), the target spec will not
support `x86-softfloat` anymore [1]. Instead, `softfloat` should be used,
which is an alias. Otherwise, one gets:
error: error loading target specification: rustc-abi: invalid rustc abi: 'x86-softfloat'. allowed values: 'x86-sse2', 'softfloat' at line 3 column 32
|
= help: run `rustc --print target-list` for a list of built-in targets
Thus conditionally use one or the other depending on the version.
The alias has existed since Rust 1.95.0 (released 2026-04-16) [2], but
use the newer version instead to avoid changing how the build works for
existing compilers, at least until more testing takes place.
Cc: Ralf Jung <post@ralfj.de>
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust/pull/157151 [1]
Link: https://github.com/rust-lang/rust/pull/151154 [2]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260530114925.260754-1-ojeda@kernel.org
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>
buf_printf() uses a fixed-size stack buffer. vsnprintf() returns the
number of bytes that *would* have been written to that buffer, which can
be larger than the size of said buffer if the formatted string is too
long.
The problem is that whenever this happens buf_printf() currently passes
this length, unchecked, to buf_write(), which silently reads past the
stack buffer and copies invalid data into the output buffer.
Fix this by detecting vsnprintf() failures and truncations before
appending to the output buffer, and report a fatal error instead of
producing corrupt symbol names.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://patch.msgid.link/20260527-nova-exports-v2-1-06de4c556d55@nvidia.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
The current minimum version of LLVM for building the kernel is 15.0.0.
However, there are two deficiencies compared to GCC that were fixed in
LLVM 17 that are starting to become more noticeable.
The first was a bug in LLVM's scope checker [1], where all labels in a
function were validated as potential targets of an asm goto statement,
even if they were not listed in the asm goto statement as targets. This
becomes particularly problematic when the cleanup attribute is used, as
asm goto(... : label_a);
...
label_a:
...
int var __free(foo);
asm goto(... : label_b);
...
label_b:
...
will trigger an error since the scope checker will complain that the
cleanup variable would be skipped when jumping from the first asm goto
to label_b (which obviously cannot happen). This issue was the catalyst
for commit e2ffa15b9b ("kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on
clang < 17"). Unfortunately, this issue is reproducible with regular asm
goto in addition to asm goto with outputs, so that change was not
entirely sufficient to avoid the issue altogether. As asm goto has
effectively been required since commit a0a12c3ed0 ("asm goto:
eradicate CC_HAS_ASM_GOTO") and the usage of the cleanup attribute
continues to grow across the tree, raising the minimum to a version that
avoids this issue altogether is a better long term solution than
attempting to workaround it at every spot where it happens.
The second issue is an incompatibility with GCC 8.1+ around variables
marked with const being valid constant expressions for _Static_assert
and other macros [2]. With GCC 8.1 being the minimum supported version
since commit 118c40b7b5 ("kbuild: require gcc-8 and binutils-2.30"),
this incompatibility becomes more of a maintenance burden since only
clang-15 and clang-16 are affected by it.
Looking at the clang version of various major distributions through
Docker images, no one should be left behind as a result of this bump, as
the old ones cannot clear the current minimum of 15.0.0.
archlinux:latest clang version 22.1.3
debian:oldoldstable-slim Debian clang version 11.0.1-2
debian:oldstable-slim Debian clang version 14.0.6
debian:stable-slim Debian clang version 19.1.7 (3+b1)
debian:testing-slim Debian clang version 21.1.8 (3+b1)
debian:unstable-slim Debian clang version 21.1.8 (7+b1)
fedora:42 clang version 20.1.8 (Fedora 20.1.8-4.fc42)
fedora:latest clang version 21.1.8 (Fedora 21.1.8-4.fc43)
fedora:44 clang version 22.1.1 (Fedora 22.1.1-2.fc44)
fedora:rawhide clang version 22.1.3 (Fedora 22.1.3-1.fc45)
opensuse/leap:latest clang version 17.0.6
opensuse/tumbleweed:latest clang version 21.1.8
ubuntu:jammy Ubuntu clang version 14.0.0-1ubuntu1.1
ubuntu:noble Ubuntu clang version 18.1.3 (1ubuntu1)
ubuntu:questing Ubuntu clang version 20.1.8 (0ubuntu4)
ubuntu:resolute Ubuntu clang version 21.1.8 (6ubuntu1)
17.0.1 is chosen as the minimum instead of 17.0.0 to ensure that the
particular version of LLVM 17 has the two aforementioned bugs fixed, as
the second was fixed during the 17.0.0 release candidate phase and it
was not until LLVM 18 that LLVM adopted the scheme of x.0.0 being a
prerelease version and x.1.0 is a release version [3] to help with
scenarios such as this.
Link: https://github.com/llvm/llvm-project/commit/f023f5cdb2e6c19026f04a15b5a935c041835d14 [1]
Link: https://github.com/llvm/llvm-project/commit/0b2d5b967d98375793897295d651f58f6fbd3034 [2]
Link: https://github.com/llvm/llvm-project/commit/4532617ae420056bf32f6403dde07fb99d276a49 [3]
Acked-by: Nicolas Schier <nsc@kernel.org>
Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-1-b3b8cda46bdd@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.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>
Pull Kbuild fixes from Nicolas Schier:
- modpost: prevent stack buffer overflow in do_input_entry() and
do_dmi_entry()
Defensively replace unbound sprintf() calls in file2alias to prevent
silent stack overflows and detect alias name overflows with proper
error message.
- kbuild: pacman-pkg: make "rc" releases adhere to pacman versioning
scheme
Enable smooth upgrades from "rc" releases w/ pacman packages.
* tag 'kbuild-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: pacman-pkg: make "rc" releases adhere to pacman versioning scheme
modpost: prevent stack buffer overflow in do_input_entry() and do_dmi_entry()
Pull misc fixes from Andrew Morton:
"14 hotfixes. 9 are for MM. 10 are cc:stable and the remainder are for
post-7.1 issues or aren't deemed suitable for backporting.
There's a two-patch MAINTAINERS series from Mike Rapoport which
updates us for the new KEXEC/KDUMP/crash/LUO/etc arrangements. And
another two-patch series from Muchun Song to fix a couple of
memory-hotplug issues. Otherwise singletons, please see the changelogs
for details"
* tag 'mm-hotfixes-stable-2026-05-18-21-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/memory: fix spurious warning when unmapping device-private/exclusive pages
mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()
drivers/base/memory: fix memory block reference leak in poison accounting
mm/memory_hotplug: fix memory block reference leak on remove
lib: kunit_iov_iter: fix test fail on powerpc
mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free
MAINTAINERS: add kexec@ list to LIVE UPDATE ENTRY
MAINTAINERS: add tree for KDUMP and KEXEC
selftests/mm: run_vmtests.sh: fix destructive tests invocation
scripts/gdb: slab: update field names of struct kmem_cache
scripts/gdb: mm: cast untyped symbols in x86_page_ops
mm/damon: fix damos_stat tracepoint format for sz_applied
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_page
The package versioning scheme does not enable smooth upgrades from "rc"
releases to the corresponding stable releases (e.g. 7.0.0-rc7 -> 7.0.0)
because pacman considers that a downgrade due to the underscore in
pkgver (e.g. 7.0.0_rc7), see e.g. vercmp(8) for an explanation of the
package version comparison used by pacman. Package versions which are
derived from said releases (e.g. built from git revisions) are
similarly affected. Fix this by modifying pkgver in order to remove the
hyphen from kernel versions containing "-rcN", where N is a
non-negative integer.
Acked-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Viktor Jägersküpper <viktor_jaegerskuepper@freenet.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260515215913.92481-1-viktor_jaegerskuepper@freenet.de
Fixes: c8578539de ("kbuild: add script and target to generate pacman package")
Signed-off-by: Nicolas Schier <nsc@kernel.org>
Several functions in scripts/mod/file2alias.c build the module alias
string by repeatedly appending into a fixed-size on-stack buffer:
char alias[256] = {};
...
sprintf(alias + strlen(alias), "%X,*", i);
This pattern is unbounded and silently corrupts the stack when the
formatted output exceeds the destination size. Two functions in this
file are realistically reachable with input that overflows their
buffer:
1. do_input_entry() appends across nine bitmap classes
(evbit/keybit/relbit/absbit/mscbit/ledbit/sndbit/ffbit/swbit). The
keybit case alone scans bits from INPUT_DEVICE_ID_KEY_MIN_INTERESTING
(0x71) to INPUT_DEVICE_ID_KEY_MAX (0x2ff), 655 iterations; if a
MODULE_DEVICE_TABLE(input, ...) populates keybit[] densely, the
emission reaches ~3132 bytes — overflowing the 256-byte buffer by
about 12x. include/linux/mod_devicetable.h declares storage for the
full bit range ("keybit[INPUT_DEVICE_ID_KEY_MAX / BITS_PER_LONG + 1]"),
so the worst case is reachable per the ABI.
2. do_dmi_entry() emits one ":<prefix>*<filtered_substr>*" segment per
matched DMI field, up to 4 matches per dmi_system_id. Each substr
is sized as char[79] in struct dmi_strmatch (mod_devicetable.h:584),
and dmi_ascii_filter() copies it verbatim into the alias buffer
without bounds. Worst case: 4 × (1 + 3 + 1 + 79 + 1) = 336 bytes
into alias[256], an 80-byte overflow.
No driver in the current tree triggers either case — every in-tree
INPUT_DEVICE_ID_MATCH_KEYBIT user populates keybit[] very sparsely
(1-3 bits), and no in-tree dmi_system_id has four maximally-long
matches. The concern is defense-in-depth: both unbounded sprintf
chains are silent stack-corruption primitives in a host build tool,
and the buffer sizes have not been revisited since the corresponding
code was first introduced.
The other do_*_entry() handlers in this file (do_usb_entry,
do_cpu_entry, do_typec_entry, ...) were audited and are bounded by
their input field sizes (uint16 IDs, fixed-length keys); their alias
buffers do not need this treatment.
Reproduced under AddressSanitizer with a stand-alone harness mirroring
do_input on a fully-populated keybit:
==18319==ERROR: AddressSanitizer: stack-buffer-overflow
WRITE of size 2 at offset 288 in frame [32, 288) 'alias'
#6 do_input poc.c:44
Stack-canary build:
Abort trap: 6 (strlen(alias)=3134, cap was 256-1)
Add a small alias_append() helper around vsnprintf with a remaining-
space check and call fatal() on overflow, matching the modpost style
for unrecoverable build conditions. do_input() takes the buffer size
as a new parameter; do_input_entry() and do_dmi_entry() pass
sizeof(alias) at every call site. dmi_ascii_filter() takes the
remaining buffer size as well and aborts on truncation. This bounds
every write into the on-stack buffers and turns the latent overflow
into a clean build error if it is ever reached.
Fixes: 1d8f430c15 ("[PATCH] Input: add modalias support")
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Hasan Basbunar <basbunarhasan@gmail.com>
Link: https://patch.msgid.link/20260505161102.44087-1-basbunarhasan@gmail.com
Signed-off-by: Nicolas Schier <nsc@kernel.org>
Steps on the way to v7.1-rc1
Resolved merge conflicts in:
include/linux/module.h
kernel/module/main.c
Cc: Siddharth Nayyar <sidnayyar@google.com>
Cc: Will McVicker <willmcvicker@google.com>
Change-Id: Ia9abf40b1600d5f67533e107e69d8c16979e2c71
Signed-off-by: Carlos Llamas <cmllamas@google.com>
In conf_askvalue(), the 'def' argument (retrieved via sym_get_string_value)
can be NULL. While current call sites ensure that 'def' is valid,
calling printf("%s\n", def) is technically undefined behavior and could
lead to a segmentation fault on certain libc implementations if the
function were called with a NULL pointer in the future.
Improve the robustness of conf_askvalue() by providing an empty string
as a fallback.
Additionally, remove the redundant re-initialization of the 'line'
buffer inside the !sym_is_changeable(sym) block, as it is already
properly initialized at the function entry.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Xingjing Deng <micro6947@gmail.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260306021709.27068-1-micro6947@gmail.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Commit 5f9ae91f7c ("kbuild: Build kernel module BTFs if BTF is enabled
and pahole supports it") in 2020 introduced CONFIG_DEBUG_INFO_BTF_MODULES
to enable generation of split BTF for kernel modules. This change required
the %.ko Makefile rule to additionally depend on vmlinux, which is used as
a base for deduplication. The regular ld_ko_o command executed by the rule
was then modified to be skipped if only vmlinux changes. This was done by
introducing a new if_changed_except command and updating the original call
to '+$(call if_changed_except,ld_ko_o,vmlinux)'.
Later, commit 214c0eea43 ("kbuild: add $(objtree)/ prefix to some
in-kernel build artifacts") in 2024 updated the rule's reference to vmlinux
from 'vmlinux' to '$(objtree)/vmlinux'. This accidentally broke the
previous logic to skip relinking modules if only vmlinux changes. The issue
is that '$(objtree)' is typically '.' and GNU Make normalizes the resulting
prerequisite './vmlinux' to just 'vmlinux', while the exclusion logic
retains the raw './vmlinux'. As a result, if_changed_except doesn't
correctly filter out vmlinux. Consequently, with
CONFIG_DEBUG_INFO_BTF_MODULES=y, modules are relinked even if only vmlinux
changes.
It is possible to fix this Makefile issue. However, having the %.ko rule
update the resulting file in place without starting from the original
inputs is rather fragile. The logic is harder to debug if something breaks
during a subsequent .ko update because the old input is lost due to the
overwrite. Additionally, it requires that the BTF processing is idempotent.
For example, sorting id+flags BTF_SET8 pairs in .BTF_ids by resolve_btfids
currently doesn't have this property.
One option is to split the %.ko target into two rules: the first for
partial linking and the second one for generating the BTF data. However,
this approach runs into an issue with requiring additional intermediate
files, which increases the size of the build directory. On my system, when
using a large distribution config with ~5500 modules, the size of the build
directory with debuginfo enabled is already ~25 GB, with .ko files
occupying ~8 GB. Duplicating these .ko files doesn't seem practical.
Measuring the speed of the %.ko processing shows that the link step is
actually relatively fast. It takes about 20% of the overall rule time,
while the BTF processing accounts for 80%. Moreover, skipping the link part
becomes relevant only during local development. In such cases, developers
typically use configs that enable a limited number of modules, so having
the %.ko rule slightly slower doesn't significantly impact the total
rebuild time. This is supported by the fact that no one has complained
about this optimization being broken for the past two years.
Therefore, remove the logic that prevents module relinking when only
vmlinux changes and simplify Makefile.modfinal.
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://patch.msgid.link/20260410131343.2519532-1-petr.pavlu@suse.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Carlos Llamas
Linus Torvalds
Ethan Nelson-Moore
James Lee
Zhou Yuhang
Siddharth Nayyar
Andrew Jones
Nathan Chancellor
Miguel Ojeda
Rong Xu
Masahiro Yamada
Alexandre Courbot
Yafang Shao
Philipp Hahn
Alice Ryhl
Viktor Jägersküpper
Hasan Basbunar
Kees Cook
Thomas Weißschuh
Illia Ostapyshyn
Xingjing Deng
Petr Pavlu