Capture the output of the patch command to detect when a patch applies
with fuzz or line offsets.
If such "fuzz" is detected during the validation phase, warn the user
and display the details. This helps identify input patches that may
need refreshing against the target source tree.
Ensure that internal patch operations (such as those in refresh_patch or
during the final build phase) can still run quietly.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/20260310203751.1479229-13-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Improve the readability of klp-build output by implementing a basic
color scheme. When the standard output and error are connected to a
terminal, highlight status messages in bold and warning/error prefixes
in yellow/red.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-12-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Provide more context for common klp-build failure modes. Clarify which
user-provided patch is unsupported or failed to apply, and explicitly
identify which kernel build (original or patched) failed.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-11-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
If .config hasn't been synced with auto.conf, any recent changes to
CONFIG_LOCALVERSION* may not get reflected in the kernel version name.
Use "make syncconfig" to force them to sync, and "make -s kernelrelease"
to get the version instead of having to construct it manually.
Fixes: 24ebfcd65a ("livepatch/klp-build: Introduce klp-build script for generating livepatch modules")
Closes: https://lore.kernel.org/20260217160645.3434685-10-joe.lawrence@redhat.com
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/20260310203751.1479229-10-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Update SHORT_CIRCUIT behavior to better handle patch validation and
argument processing in later klp-build steps.
Perform patch validation for both step 1 (building original kernel) and
step 2 (building patched kernel) to ensure patches are verified before
any compilation occurs.
Additionally, allow the user to omit input patches when skipping past
step 2.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-9-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Fix or suppress the following shellcheck warnings:
In klp-build line 57:
command grep "$@" || true
^--^ SC2317 (info): Command appears to be unreachable. Check usage (or ignore if invoked indirectly).
Fix the following warning:
In klp-build line 565:
local file_dir="$(dirname "$file")"
^------^ SC2034 (warning): file_dir appears unused. Verify use (or export if used externally).
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-8-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Provide a custom grep() function to catch direct usage of the command.
Bare grep calls are generally incompatible with pipefail and
errexit behavior (where a failed match causes the script to exit).
Developers can still call grep via command grep if that behavior is
explicitly desired.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-6-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The klp-build script is currently very strict with input patches,
requiring them to apply cleanly via `git apply --recount`. This
prevents the use of patches with minor contextual fuzz relative to the
target kernel sources.
To allow users to reuse a patch across similar kernel streams, switch to
using GNU patch and patchutils for intermediate patch manipulation.
Update the logic for applying, reverting, and regenerating patches:
- Use 'patch -p1' for better handling of context fuzz.
- Use 'recountdiff' to update line counts after FIX_PATCH_LINES.
- Drop git_refresh() and related git-specific logic.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/20260310203751.1479229-5-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The klp-build script prepares a clean patch by populating two temporary
directories ('a' and 'b') with source files and diffing the result.
However, this process fails when a patch introduces a new source file,
as the script attempts to copy files that do not yet exist in the
original source tree. Likewise, it fails when a patch removes a source
file and the script attempts to copy a file that no longer exists.
Refactor the file-gathering logic to distinguish between original input
files and patched output files:
- Split get_patch_files() into get_patch_input_files() and
get_patch_output_files() to identify which files exist before and
after patch application.
- Filter out "/dev/null" from both to handle file creation/deletion.
- Update refresh_patch() to only copy existing input files to the 'a'
directory and the resulting output files to the 'b' directory.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-4-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Some special sections specify their ELF section entsize, for example:
.pushsection section, "M", @progbits, 8
The entsize (8 in this example) is needed by objtool klp-diff for
extracting individual entries.
Clang assembler versions older than 20 silently ignore the above
construct and set entsize to 0, resulting in the following error:
.discard.annotate_data: missing special section entsize or annotations
Add a klp-build check to prevent the use of Clang assembler versions
prior to 20.
Fixes: 24ebfcd65a ("livepatch/klp-build: Introduce klp-build script for generating livepatch modules")
Reported-by: Song Liu <song@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/957fd52e375d0e2cfa3ac729160da995084a7f5e.1769562556.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
When building a patch to a single-file kernel module with
CONFIG_MODULE_SRCVERSION_ALL enabled, the klp-build module link fails in
modpost:
Diffing objects
drivers/md/raid0.o: changed function: raid0_run
Building patch module: livepatch-0001-patch-raid0_run.ko
drivers/md/raid0.c: No such file or directory
...
The problem here is that klp-build copied drivers/md/.raid0.o.cmd to the
module build directory, but it didn't also copy over the input source
file listed in the .cmd file:
source_drivers/md/raid0.o := drivers/md/raid0.c
So modpost dies due to the missing .c file which is needed for
calculating checksums for CONFIG_MODULE_SRCVERSION_ALL.
Instead of copying the original .cmd file, just create an empty one.
Modpost only requires that it exists. The original object's build
dependencies are irrelevant for the frankenobjects used by klp-build.
Fixes: 24ebfcd65a ("livepatch/klp-build: Introduce klp-build script for generating livepatch modules")
Reported-by: Song Liu <song@kernel.org>
Tested-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/c41b6629e02775e4c1015259aa36065b3fe2f0f3.1769471792.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
With CONFIG_KLP_BUILD enabled, checksums are only needed during a
klp-build run. There's no need to enable them for normal kernel builds.
This also has the benefit of softening the xxhash dependency.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://patch.msgid.link/edbb1ca215e4926e02edb493b68b9d6d063e902f.1762990139.git.jpoimboe@kernel.org
Add a --show-first-changed option to identify where changed functions
begin to diverge:
- Parse 'objtool klp diff' output to find changed functions.
- Run objtool again on each object with --debug-checksum=<funcs>.
- Diff the per-instruction checksum debug output to locate the first
differing instruction.
This can be useful for quickly determining where and why a function
changed.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add a --debug option which gets passed to "objtool klp diff" to enable
debug output related to cloning decisions.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add a klp-build script which automates the generation of a livepatch
module from a source .patch file by performing the following steps:
- Builds an original kernel with -function-sections and
-fdata-sections, plus objtool function checksumming.
- Applies the .patch file and rebuilds the kernel using the same
options.
- Runs 'objtool klp diff' to detect changed functions and generate
intermediate binary diff objects.
- Builds a kernel module which links the diff objects with some
livepatch module init code (scripts/livepatch/init.c).
- Finalizes the livepatch module (aka work around linker wreckage)
using 'objtool klp post-link'.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
