Commit Graph
36 Commits
Author SHA1 Message Date
Josh Poimboeuf 225d16dd51 klp-build: Validate short-circuit prerequisites
The --short-circuit option implicitly requires that certain directories
are already in klp-tmp.  Enforce that to prevent confusing errors.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:06 -07:00
Josh Poimboeuf 3b8e56b86f objtool/klp: Remove "objtool --checksum"
The checksum functionality has been moved to "objtool klp checksum"
which is now used by klp-build.  Remove the now-dead --checksum and
--debug-checksum options from the default objtool command.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:05 -07:00
Josh Poimboeuf d4888d5804 klp-build: Use "objtool klp checksum" subcommand
Use the new "objtool klp checksum" subcommand instead of injecting
--checksum into every objtool invocation via OBJTOOL_ARGS during the
kernel build.

This decouples checksum generation from the build, running it in
separate post-build passes, making the code (and the patch generation
pipeline itself) more modular.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:05 -07:00
Josh Poimboeuf b6480aaedf klp-build: Remove redundant SRC and OBJ variables
SRC and OBJ are both set to $(pwd) and are always identical.  The script
already enforces that klp-build runs from the kernel root directory, and
builds are done in-place, making these variables unnecessary.

Suggested-by: Song Liu <song@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:04 -07:00
Josh Poimboeuf e950d2a10a klp-build: Print "objtool klp diff" command in verbose mode
Print the full objtool command line when '--verbose' is given to help
with debugging.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:04 -07:00
Josh Poimboeuf df0d7bb04a klp-build: Reject patches to realmode
Realmode code is compiled as a separate 16-bit binary and embedded into
the kernel image via rmpiggy.S.  It can't be livepatched.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:03 -07:00
Josh Poimboeuf d8c3e26236 klp-build: Reject patches to vDSO
vDSO code runs in userspace and can't be livepatched.  Such patches also
cause spurious "new function" errors due to generated files like
vdso*-image.c having unstable line numbers across builds.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:03 -07:00
Josh Poimboeuf f3048888ea klp-build: Fix patch cleanup on interrupt
If a build error occurs and the user hits Ctrl-C while a large patch is
being reverted during cleanup, the cleanup EXIT trap gets re-triggered
and tries to re-revert the already partially-reverted patch.  That
causes 'patch -R' to repeatedly prompt

  "Unreversed patch detected!  Ignore -R? [n]"

for each already-reverted hunk, with no way to break out.

Fix it by adding '--force' to the patch revert command in
revert_patch(), which causes it to silently ignore already-reverted
hunks.  And ignore errors, as the cleanup is always best-effort.

For similar reasons, add to APPLIED_PATCHES before (rather than after)
applying the patch in apply_patch() so an interrupted apply will also
get cleaned up.

Fixes: d36a7343f4 ("livepatch/klp-build: switch to GNU patch and recountdiff")
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:03 -07:00
Josh Poimboeuf 9652454374 klp-build: Suppress excessive fuzz output by default
When a patch applies with fuzz, the detailed output from the patch tool
can be very noisy, especially for big patches.

Suppress the fuzz details by default, while keeping the "applied with
fuzz" warning.  The noise can be restored with '--verbose'.

Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:03 -07:00
Josh Poimboeuf b3ece3019e klp-build: Validate patch file existence
Make sure all patch files actually exist.  Otherwise there can be
confusing errors later.

Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:03 -07:00
Josh Poimboeuf 946d3510fe klp-build: Don't use errexit
The errtrace option (combined with the ERR trap) already serves the same
function (and more) as errexit, so errexit is redundant.  And it has
more pitfalls.  Remove it.

Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:03 -07:00
Josh Poimboeuf ba77fe5578 klp-build: Fix checksum comparison for changed offsets
The klp-build -f/--show-first-changed feature uses diff to compare
checksum log lines between original and patched objects.  However, diff
compares entire lines, including the offset field.  When a function is
at a different section offset, the offset field differs even though the
instruction checksum is identical, causing the wrong instruction to be
printed.

Only compare the checksum field when looking for the first changed
instruction.  Also print both the original and patched offsets when they
differ.

Fixes: 78be9facfb ("livepatch/klp-build: Add --show-first-changed option to show function divergence")
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:02 -07:00
Josh Poimboeuf cc39ccce7d klp-build: Fix hang on out-of-date .config
If .config is out of date with the kernel source, 'make syncconfig'
hangs while waiting for user input on new config options.  Detect the
mismatch and return an error.

Fixes: 6f93f7b068 ("livepatch/klp-build: Fix inconsistent kernel version")
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-05-04 21:16:02 -07:00
Linus Torvalds 4b2bdc2221 Merge tag 'objtool-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool updates from Ingo Molnar:

 - KLP support updates and fixes (Song Liu)

 - KLP-build script updates and fixes (Joe Lawrence)

 - Support Clang RAX DRAP sequence, to address clang false positive
   (Josh Poimboeuf)

 - Reorder ORC register numbering to match regular x86 register
   numbering (Josh Poimboeuf)

 - Misc cleanups (Wentong Tian, Song Liu)

* tag 'objtool-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool/x86: Reorder ORC register numbering
  objtool: Support Clang RAX DRAP sequence
  livepatch/klp-build: report patch validation fuzz
  livepatch/klp-build: add terminal color output
  livepatch/klp-build: provide friendlier error messages
  livepatch/klp-build: improve short-circuit validation
  livepatch/klp-build: fix shellcheck complaints
  livepatch/klp-build: add Makefile with check target
  livepatch/klp-build: add grep-override function
  livepatch/klp-build: switch to GNU patch and recountdiff
  livepatch/klp-build: support patches that add/remove files
  objtool/klp: Correlate locals to globals
  objtool/klp: Match symbols based on demangled_name for global variables
  objtool/klp: Remove .llvm suffix in demangle_name()
  objtool/klp: Also demangle global objects
  objtool/klp: Use sym->demangled_name for symbol_name hash
  objtool/klp: Remove trailing '_' in demangle_name()
  objtool/klp: Remove redundant strcmp() in correlate_symbols()
  objtool: Use section/symbol type helpers
2026-04-14 13:00:04 -07:00
Joe LawrenceandJosh Poimboeuf 51a0b7c4ed livepatch/klp-build: report patch validation fuzz
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>
2026-03-16 12:52:53 -07:00
Joe LawrenceandJosh Poimboeuf 1fbc9b855f livepatch/klp-build: add terminal color output
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>
2026-03-16 12:52:53 -07:00
Joe LawrenceandJosh Poimboeuf b41d8b7d17 livepatch/klp-build: provide friendlier error messages
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>
2026-03-16 12:52:53 -07:00
Josh Poimboeuf 6f93f7b068 livepatch/klp-build: Fix inconsistent kernel version
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>
2026-03-16 12:50:17 -07:00
Joe LawrenceandJosh Poimboeuf e506ad210d livepatch/klp-build: improve short-circuit validation
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>
2026-03-16 12:46:49 -07:00
Joe LawrenceandJosh Poimboeuf b4a5351939 livepatch/klp-build: fix shellcheck complaints
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>
2026-03-16 12:46:49 -07:00
Joe LawrenceandJosh Poimboeuf 0573bcc4ff livepatch/klp-build: add Makefile with check target
Add a standalone Makefile with a 'check' target that runs static code
analysis (shellcheck) on the klp-build script(s).  This is intended
strictly as a development aid.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Link: https://patch.msgid.link/20260310203751.1479229-7-joe.lawrence@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-03-16 12:46:48 -07:00
Joe LawrenceandJosh Poimboeuf e4dbf70615 livepatch/klp-build: add grep-override function
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>
2026-03-16 12:46:48 -07:00
Joe LawrenceandJosh Poimboeuf d36a7343f4 livepatch/klp-build: switch to GNU patch and recountdiff
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>
2026-03-16 12:46:48 -07:00
Joe LawrenceandJosh Poimboeuf 757bd10ff0 livepatch/klp-build: support patches that add/remove files
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>
2026-03-16 12:46:48 -07:00
Linus Torvalds bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00