linux.git/tools/objtool, branch v6.18.21

objtool: Handle Clang RSP musical chairs

2026-04-02T11:23:01+00:00

[ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ]

For no apparent reason (possibly related to CONFIG_KMSAN), Clang can
randomly pass the value of RSP to other registers and then back again to
RSP.  Handle that accordingly.

Fixes the following warnings:

  drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state
  drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1

Reported-by: Arnd Bergmann 
Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com
Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Sasha Levin

kbuild: Leave objtool binary around with 'make clean'

2026-03-19T15:08:50+00:00

[ Upstream commit fdb12c8a24a453bdd6759979b6ef1e04ebd4beb4 ]

The difference between 'make clean' and 'make mrproper' is documented in
'make help' as:

  clean     - Remove most generated files but keep the config and
              enough build support to build external modules
  mrproper  - Remove all generated files + config + various backup files

After commit 68b4fe32d737 ("kbuild: Add objtool to top-level clean
target"), running 'make clean' then attempting to build an external
module with the resulting build directory fails with

  $ make ARCH=x86_64 O=build clean

  $ make -C build M=... MO=...
  ...
  /bin/sh: line 1: .../build/tools/objtool/objtool: No such file or directory

as 'make clean' removes the objtool binary.

Split the objtool clean target into mrproper and clean like Kbuild does
and remove all generated artifacts with 'make clean' except for the
objtool binary, which is removed with 'make mrproper'. To avoid a small
race when running the objtool clean target through both objtool_mrproper
and objtool_clean when running 'make mrproper', modify objtool's clean
up find command to avoid using find's '-delete' command by piping the
files into 'xargs rm -f' like the rest of Kbuild does.

Cc: stable@vger.kernel.org
Fixes: 68b4fe32d737 ("kbuild: Add objtool to top-level clean target")
Reported-by: Michal Suchanek 
Closes: https://lore.kernel.org/20260225112633.6123-1-msuchanek@suse.de/
Reported-by: Rainer Fiebig 
Closes: https://lore.kernel.org/62d12399-76e5-3d40-126a-7490b4795b17@mailbox.org/
Acked-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Reviewed-by: Nicolas Schier 
Tested-by: Nicolas Schier 
Link: https://patch.msgid.link/20260227-avoid-objtool-binary-removal-clean-v1-1-122f3e55eae9@kernel.org
Signed-off-by: Nathan Chancellor 
[ Context ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

kbuild: Add objtool to top-level clean target

2026-02-26T22:59:36+00:00

[ Upstream commit 68b4fe32d73789dea23e356f468de67c8367ef8f ]

Objtool is an integral part of the build, make sure it gets cleaned by
"make clean" and "make mrproper".

Fixes: 442f04c34a1a ("objtool: Add tool to perform compile-time stack metadata validation")
Reported-by: Jens Remus 
Closes: https://lore.kernel.org/15f2af3b-be33-46fc-b972-6b8e7e0aa52e@linux.ibm.com
Signed-off-by: Josh Poimboeuf 
Tested-by: Jens Remus 
Link: https://patch.msgid.link/968faf2ed30fa8b3519f79f01a1ecfe7929553e5.1770759919.git.jpoimboe@kernel.org
[nathan: use Closes: instead of Link: per checkpatch.pl]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Sasha Levin

objtool: Fix weak symbol detection

2025-12-18T13:02:28+00:00

[ Upstream commit 72567c630d32bc31f671977f78228c80937ed80e ]

find_symbol_hole_containing() fails to find a symbol hole (aka stripped
weak symbol) if its section has no symbols before the hole.  This breaks
weak symbol detection if -ffunction-sections is enabled.

Fix that by allowing the interval tree to contain section symbols, which
are always at offset zero for a given section.

Fixes a bunch of (-ffunction-sections) warnings like:

  vmlinux.o: warning: objtool: .text.__x64_sys_io_setup+0x10: unreachable instruction

Fixes: 4adb23686795 ("objtool: Ignore extra-symbol code")
Acked-by: Petr Mladek 
Tested-by: Joe Lawrence 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Sasha Levin

objtool: Fix standalone --hacks=jump_label

2025-12-18T13:02:28+00:00

[ Upstream commit be8374a5ba7cbab6b97df94b4ffe0b92f5c8a6d2 ]

The objtool command line 'objtool --hacks=jump_label foo.o' on its own
should be expected to rewrite jump labels to NOPs. This means the
add_special_section_alts() code path needs to run when only this option
is provided.

This is mainly relevant in certain debugging situations, but could
potentially also fix kernel builds in which objtool is run with
--hacks=jump_label but without --orc, --stackval, --uaccess, or
--hacks=noinstr.

Fixes: de6fbcedf5ab ("objtool: Read special sections with alts only when specific options are selected")
Signed-off-by: Dylan Hatch 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Sasha Levin

objtool: Fix skip_alt_group() for non-alternative STAC/CLAC

2025-11-01T06:43:20+00:00

If an insn->alt points to a STAC/CLAC instruction, skip_alt_group()
assumes it's part of an alternative ("alt group") as opposed to some
other kind of "alt" such as an exception fixup.

While that assumption may hold true in the current code base, Linus has
an out-of-tree patch which breaks that assumption by replacing the
STAC/CLAC alternatives with raw STAC/CLAC instructions.

Make skip_alt_group() more robust by making sure it's actually an alt
group before continuing.

Reported-by: Linus Torvalds 
Fixes: 2d12c6fb7875 ("objtool: Remove ANNOTATE_IGNORE_ALTERNATIVE from CLAC/STAC")
Closes: https://lore.kernel.org/CAHk-=wi6goUT36sR8GE47_P-aVrd5g38=VTRHpktWARbyE-0ow@mail.gmail.com
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Tested-by: Linus Torvalds 
Link: https://patch.msgid.link/3d22415f7b8e06a64e0873b21f48389290eeaa49.1761767616.git.jpoimboe@kernel.org

objtool: Fix failure when being compiled on x32 system

2025-10-22T13:21:55+00:00

Fix compilation failure when compiling the kernel with the x32 toolchain.

In file included from check.c:16:
check.c: In function ¡check_abs_references¢:
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:47:17: error: format ¡%lx¢ expects argument of type ¡long unsigned int¢, but argument 7 has type ¡u64¢ {aka ¡long
long unsigned int¢} [-Werror=format=]
   47 |                 "%s%s%s: objtool" extra ": " format "\n",               \
      |                 ^~~~~~~~~~~~~~~~~
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:54:9: note: in expansion of macro ¡___WARN¢
   54 |         ___WARN(severity, "", format, ##__VA_ARGS__)
      |         ^~~~~~~
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:74:27: note: in expansion of macro ¡__WARN¢
   74 | #define WARN(format, ...) __WARN(WARN_STR, format, ##__VA_ARGS__)
      |                           ^~~~~~
check.c:4713:33: note: in expansion of macro ¡WARN¢
 4713 |                                 WARN("section %s has absolute relocation at offset 0x%lx",
      |                                 ^~~~

Fixes: 0d6e4563fc03 ("objtool: Add action to check for absence of absolute relocations")
Signed-off-by: Mikulas Patocka 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Ard Biesheuvel 
Link: https://patch.msgid.link/1ac32fff-2e67-5155-f570-69aad5bf5412@redhat.com

objtool/rust: add one more `noreturn` Rust function

2025-10-22T13:21:54+00:00

Between Rust 1.79 and 1.86, under `CONFIG_RUST_KERNEL_DOCTESTS=y`,
`objtool` may report:

    rust/doctests_kernel_generated.o: warning: objtool:
    rust_doctest_kernel_alloc_kbox_rs_13() falls through to next
    function rust_doctest_kernel_alloc_kvec_rs_0()

(as well as in rust_doctest_kernel_alloc_kvec_rs_0) due to calls to the
`noreturn` symbol:

    core::option::expect_failed

from code added in commits 779db37373a3 ("rust: alloc: kvec: implement
AsPageIter for VVec") and 671618432f46 ("rust: alloc: kbox: implement
AsPageIter for VBox").

Thus add the mangled one to the list so that `objtool` knows it is
actually `noreturn`.

This can be reproduced as well in other versions by tweaking the code,
such as the latest stable Rust (1.90.0).

Stable does not have code that triggers this, but it could have it in
the future. Downstream forks could too. Thus tag it for backport.

See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
for more details.

Signed-off-by: Miguel Ojeda 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Alice Ryhl 
Cc: stable@vger.kernel.org # Needed in 6.12.y and later.
Link: https://patch.msgid.link/20251020020714.2511718-1-ojeda@kernel.org

Merge tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-10-11T18:19:16+00:00

Pull more x86 updates from Borislav Petkov:

 - Remove a bunch of asm implementing condition flags testing in KVM's
   emulator in favor of int3_emulate_jcc() which is written in C

 - Replace KVM fastops with C-based stubs which avoids problems with the
   fastop infra related to latter not adhering to the C ABI due to their
   special calling convention and, more importantly, bypassing compiler
   control-flow integrity checking because they're written in asm

 - Remove wrongly used static branches and other ugliness accumulated
   over time in hyperv's hypercall implementation with a proper static
   function call to the correct hypervisor call variant

 - Add some fixes and modifications to allow running FRED-enabled
   kernels in KVM even on non-FRED hardware

 - Add kCFI improvements like validating indirect calls and prepare for
   enabling kCFI with GCC. Add cmdline params documentation and other
   code cleanups

 - Use the single-byte 0xd6 insn as the official #UD single-byte
   undefined opcode instruction as agreed upon by both x86 vendors

 - Other smaller cleanups and touchups all over the place

* tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86,retpoline: Optimize patch_retpoline()
  x86,ibt: Use UDB instead of 0xEA
  x86/cfi: Remove __noinitretpoline and __noretpoline
  x86/cfi: Add "debug" option to "cfi=" bootparam
  x86/cfi: Standardize on common "CFI:" prefix for CFI reports
  x86/cfi: Document the "cfi=" bootparam options
  x86/traps: Clarify KCFI instruction layout
  compiler_types.h: Move __nocfi out of compiler-specific header
  objtool: Validate kCFI calls
  x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y
  x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware
  x86/fred: Install system vector handlers even if FRED isn't fully enabled
  x86/hyperv: Use direct call to hypercall-page
  x86/hyperv: Clean up hv_do_hypercall()
  KVM: x86: Remove fastops
  KVM: x86: Convert em_salc() to C
  KVM: x86: Introduce EM_ASM_3WCL
  KVM: x86: Introduce EM_ASM_1SRC2
  KVM: x86: Introduce EM_ASM_2CL
  KVM: x86: Introduce EM_ASM_2W
  ...

Merge tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

2025-10-02T03:58:51+00:00

Pull Kbuild updates from Nathan Chancellor:

 - Extend modules.builtin.modinfo to include module aliases from
   MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such
   as kmod) can verify that a particular module alias will be handled by
   a builtin module

 - Bump the minimum version of LLVM for building the kernel to 15.0.0

 - Upgrade several userspace API checks in headers_check.pl to errors

 - Unify and consolidate CONFIG_WERROR / W=e handling

 - Turn assembler and linker warnings into errors with CONFIG_WERROR /
   W=e

 - Respect CONFIG_WERROR / W=e when building userspace programs
   (userprogs)

 - Enable -Werror unconditionally when building host programs
   (hostprogs)

 - Support copy_file_range() and data segment alignment in gen_init_cpio
   to improve performance on filesystems that support reflinks such as
   btrfs and XFS

 - Miscellaneous small changes to scripts and configuration files

* tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (47 commits)
  modpost: Initialize builtin_modname to stop SIGSEGVs
  Documentation: kbuild: note CONFIG_DEBUG_EFI in reproducible builds
  kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o
  modpost: Create modalias for builtin modules
  modpost: Add modname to mod_device_table alias
  scsi: Always define blogic_pci_tbl structure
  kbuild: extract modules.builtin.modinfo from vmlinux.unstripped
  kbuild: keep .modinfo section in vmlinux.unstripped
  kbuild: always create intermediate vmlinux.unstripped
  s390: vmlinux.lds.S: Reorder sections
  KMSAN: Remove tautological checks
  objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY
  lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
  riscv: Remove ld.lld version checks from many TOOLCHAIN_HAS configs
  riscv: Unconditionally use linker relaxation
  riscv: Remove version check for LTO_CLANG selects
  powerpc: Drop unnecessary initializations in __copy_inst_from_kernel_nofault()
  mips: Unconditionally select ARCH_HAS_CURRENT_STACK_POINTER
  arm64: Remove tautological LLVM Kconfig conditions
  ARM: Clean up definition of ARM_HAS_GROUP_RELOCS
  ...