linux-toradex.git/tools/bpf/resolve_btfids, branch master Linux kernel for Apalis and Colibri modules resolve_btfids: Fix linker flags detection 2026-03-07T16:51:51+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2026-03-05T01:47:30+00:00 b0dcdcb9ae757c8a8ba2fb24d34f8d147bae707b The "|| echo -lzstd" default makes zstd an unconditional link dependency of resolve_btfids. On systems where libzstd-dev is not installed and pkg-config fails, the linker fails: ld: cannot find -lzstd: No such file or directory libzstd is a transitive dependency of libelf, so the -lzstd flag is strictly necessary only for static builds [1]. Remove ZSTD_LIBS variable, and instead set LIBELF_LIBS depending on whether the build is static or not. Use $(HOSTPKG_CONFIG) as primary source of the flags list. Also add a default value for HOSTPKG_CONFIG in case it's not built via the toplevel Makefile. Pass it from selftests/bpf too. [1] https://lore.kernel.org/bpf/4ff82800-2daa-4b9f-95a9-6f512859ee70@linux.dev/ Reported-by: BPF CI Bot (Claude Opus 4.6) <bot+bpf-ci@kernel.org> Reported-by: Vitaly Chikunov <vt@altlinux.org> Closes: https://lore.kernel.org/bpf/aaWqMcK-2AQw5dx8@altlinux.org/ Fixes: 4021848a903e ("selftests/bpf: Pass through build flags to bpftool and resolve_btfids") Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Reviewed-by: Paul Chaignon <paul.chaignon@gmail.com> Link: https://lore.kernel.org/r/20260305014730.3123382-1-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
The "|| echo -lzstd" default makes zstd an unconditional link
dependency of resolve_btfids. On systems where libzstd-dev is not
installed and pkg-config fails, the linker fails:

  ld: cannot find -lzstd: No such file or directory

libzstd is a transitive dependency of libelf, so the -lzstd flag is
strictly necessary only for static builds [1].

Remove ZSTD_LIBS variable, and instead set LIBELF_LIBS depending on
whether the build is static or not. Use $(HOSTPKG_CONFIG) as primary
source of the flags list.

Also add a default value for HOSTPKG_CONFIG in case it's not built via
the toplevel Makefile. Pass it from selftests/bpf too.

[1] https://lore.kernel.org/bpf/4ff82800-2daa-4b9f-95a9-6f512859ee70@linux.dev/

Reported-by: BPF CI Bot (Claude Opus 4.6) <bot+bpf-ci@kernel.org>
Reported-by: Vitaly Chikunov <vt@altlinux.org>
Closes: https://lore.kernel.org/bpf/aaWqMcK-2AQw5dx8@altlinux.org/
Fixes: 4021848a903e ("selftests/bpf: Pass through build flags to bpftool and resolve_btfids")
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Reviewed-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/20260305014730.3123382-1-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
resolve_btfids: Fix memory leaks reported by ASAN 2026-02-24T16:19:49+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2026-02-23T19:07:23+00:00 c5c1e313493cd836863bb673bb2b8beaa915cad9 Running resolve_btfids with ASAN reveals memory leaks in btf_id handling. - Change get_id() to use a local buffer - Make btf_id__add() strdup the name internally - Add btf_id__free_all() that frees all nodese of a tree - Call the cleanup function on exit for every tree Acked-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Link: https://lore.kernel.org/r/20260223190736.649171-8-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Running resolve_btfids with ASAN reveals memory leaks in btf_id
handling.

- Change get_id() to use a local buffer
- Make btf_id__add() strdup the name internally
- Add btf_id__free_all() that frees all nodese of a tree
- Call the cleanup function on exit for every tree

Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260223190736.649171-8-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
selftests/bpf: Pass through build flags to bpftool and resolve_btfids 2026-02-24T16:19:49+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2026-02-23T19:07:22+00:00 4021848a903e65f74cf88997c12b96d6bc2453e6 EXTRA_* and SAN_* build flags were not correctly propagated to bpftool and resolve_btids when building selftests/bpf. This led to various build errors on attempt to build with SAN_CFLAGS="-fsanitize=address", for example. Fix the makefiles to address this: - Pass SAN_CFLAGS/SAN_LDFLAGS to bpftool and resolve_btfids build - Propagate EXTRA_LDFLAGS to resolve_btfids link command - Use pkg-config to detect zlib and zstd for resolve_btfids, similar libelf handling Also check for ASAN flag in selftests/bpf/Makefile for convenience. Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Link: https://lore.kernel.org/r/20260223190736.649171-7-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
EXTRA_* and SAN_* build flags were not correctly propagated to bpftool
and resolve_btids when building selftests/bpf. This led to various
build errors on attempt to build with SAN_CFLAGS="-fsanitize=address",
for example.

Fix the makefiles to address this:
  - Pass SAN_CFLAGS/SAN_LDFLAGS to bpftool and resolve_btfids build
  - Propagate EXTRA_LDFLAGS to resolve_btfids link command
  - Use pkg-config to detect zlib and zstd for resolve_btfids, similar
    libelf handling

Also check for ASAN flag in selftests/bpf/Makefile for convenience.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260223190736.649171-7-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
resolve_btfids: Refactor the sort_btf_by_name function 2026-02-04T18:17:19+00:00 Donglin Peng pengdonglin@xiaomi.com 2026-02-02T12:01:14+00:00 5e6e1dc43a217624087ce45bafd20ac2cfb3c190 Preserve original relative order of anonymous or same-named types to improve the consistency. No functional changes. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260202120114.3707141-1-dolinux.peng@gmail.com 
Preserve original relative order of anonymous or same-named
types to improve the consistency.

No functional changes.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260202120114.3707141-1-dolinux.peng@gmail.com
resolve_btfids: Support for KF_IMPLICIT_ARGS 2026-01-21T00:15:57+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2026-01-20T22:26:30+00:00 9d199965990c0b21160c565076b93725d6638c28 Implement BTF modifications in resolve_btfids to support BPF kernel functions with implicit arguments. For a kfunc marked with KF_IMPLICIT_ARGS flag, a new function prototype is added to BTF that does not have implicit arguments. The kfunc's prototype is then updated to a new one in BTF. This prototype is the intended interface for the BPF programs. A <func_name>_impl function is added to BTF to make the original kfunc prototype searchable for the BPF verifier. If a <func_name>_impl function already exists in BTF, its interpreted as a legacy case, and this step is skipped. Whether an argument is implicit is determined by its type: currently only `struct bpf_prog_aux *` is supported. As a result, the BTF associated with kfunc is changed from __bpf_kfunc bpf_foo(int arg1, struct bpf_prog_aux *aux); into bpf_foo_impl(int arg1, struct bpf_prog_aux *aux); __bpf_kfunc bpf_foo(int arg1); For more context see previous discussions and patches [1][2]. [1] https://lore.kernel.org/dwarves/ba1650aa-fafd-49a8-bea4-bdddee7c38c9@linux.dev/ [2] https://lore.kernel.org/bpf/20251029190113.3323406-1-ihor.solodrai@linux.dev/ Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Link: https://lore.kernel.org/r/20260120222638.3976562-6-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Implement BTF modifications in resolve_btfids to support BPF kernel
functions with implicit arguments.

For a kfunc marked with KF_IMPLICIT_ARGS flag, a new function
prototype is added to BTF that does not have implicit arguments. The
kfunc's prototype is then updated to a new one in BTF. This prototype
is the intended interface for the BPF programs.

A <func_name>_impl function is added to BTF to make the original kfunc
prototype searchable for the BPF verifier. If a <func_name>_impl
function already exists in BTF, its interpreted as a legacy case, and
this step is skipped.

Whether an argument is implicit is determined by its type:
currently only `struct bpf_prog_aux *` is supported.

As a result, the BTF associated with kfunc is changed from

    __bpf_kfunc bpf_foo(int arg1, struct bpf_prog_aux *aux);

into

    bpf_foo_impl(int arg1, struct bpf_prog_aux *aux);
    __bpf_kfunc bpf_foo(int arg1);

For more context see previous discussions and patches [1][2].

[1] https://lore.kernel.org/dwarves/ba1650aa-fafd-49a8-bea4-bdddee7c38c9@linux.dev/
[2] https://lore.kernel.org/bpf/20251029190113.3323406-1-ihor.solodrai@linux.dev/

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-6-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
resolve_btfids: Introduce finalize_btf() step 2026-01-21T00:15:56+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2026-01-20T22:26:29+00:00 2583e81fd8852e6cf6730c4463b6580deb7a8aad Since recently [1][2] resolve_btfids executes final adjustments to the kernel/module BTF before it's embedded into the target binary. To keep the implementation simple, a clear and stable "pipeline" of how BTF data flows through resolve_btfids would be helpful. Some BTF modifications may change the ids of the types, so it is important to maintain correct order of operations with respect to .BTF_ids resolution too. This patch refactors the BTF handling to establish the following sequence: - load target ELF sections - load .BTF_ids symbols - this will be a dependency of btf2btf transformations in subsequent patches - load BTF and its base as is - (*) btf2btf transformations will happen here - finalize_btf(), introduced in this patch - does distill base and sort BTF - resolve and patch .BTF_ids This approach helps to avoid fixups in .BTF_ids data in case the ids change at any point of BTF processing, because symbol resolution happens on the finalized, ready to dump, BTF data. This also gives flexibility in BTF transformations, because they will happen on BTF that is not distilled and/or sorted yet, allowing to freely add, remove and modify BTF types. [1] https://lore.kernel.org/bpf/20251219181321.1283664-1-ihor.solodrai@linux.dev/ [2] https://lore.kernel.org/bpf/20260109130003.3313716-1-dolinux.peng@gmail.com/ Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Link: https://lore.kernel.org/r/20260120222638.3976562-5-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Since recently [1][2] resolve_btfids executes final adjustments to the
kernel/module BTF before it's embedded into the target binary.

To keep the implementation simple, a clear and stable "pipeline" of
how BTF data flows through resolve_btfids would be helpful. Some BTF
modifications may change the ids of the types, so it is important to
maintain correct order of operations with respect to .BTF_ids
resolution too.

This patch refactors the BTF handling to establish the following
sequence:
  - load target ELF sections
  - load .BTF_ids symbols
    - this will be a dependency of btf2btf transformations in
      subsequent patches
  - load BTF and its base as is
  - (*) btf2btf transformations will happen here
  - finalize_btf(), introduced in this patch
    - does distill base and sort BTF
  - resolve and patch .BTF_ids

This approach helps to avoid fixups in .BTF_ids data in case the ids
change at any point of BTF processing, because symbol resolution
happens on the finalized, ready to dump, BTF data.

This also gives flexibility in BTF transformations, because they will
happen on BTF that is not distilled and/or sorted yet, allowing to
freely add, remove and modify BTF types.

[1] https://lore.kernel.org/bpf/20251219181321.1283664-1-ihor.solodrai@linux.dev/
[2] https://lore.kernel.org/bpf/20260109130003.3313716-1-dolinux.peng@gmail.com/

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-5-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
tools/resolve_btfids: Support BTF sorting feature 2026-01-14T00:10:39+00:00 Donglin Peng pengdonglin@xiaomi.com 2026-01-09T12:59:55+00:00 230e7d7de5a8d2bcda2a5cdcc8c176c09a63e331 This introduces a new BTF sorting phase that specifically sorts BTF types by name in ascending order, so that the binary search can be used to look up types. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20260109130003.3313716-4-dolinux.peng@gmail.com 
This introduces a new BTF sorting phase that specifically sorts
BTF types by name in ascending order, so that the binary search
can be used to look up types.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-4-dolinux.peng@gmail.com
resolve_btfids: Implement --patch_btfids 2025-12-31T17:04:09+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2025-12-31T01:25:57+00:00 1a8fa7faf4890d201aad4f5d4943f74d840cd0ba Recent changes in BTF generation [1] rely on ${OBJCOPY} command to update .BTF_ids section data in target ELF files. This exposed a bug in llvm-objcopy --update-section code path, that may lead to corruption of a target ELF file. Specifically, because of the bug st_shndx of some symbols may be (incorrectly) set to 0xffff (SHN_XINDEX) [2][3]. While there is a pending fix for LLVM, it'll take some time before it lands (likely in 22.x). And the kernel build must keep working with older LLVM toolchains in the foreseeable future. Using GNU objcopy for .BTF_ids update would work, but it would require changes to LLVM-based build process, likely breaking existing build environments as discussed in [2]. To work around llvm-objcopy bug, implement --patch_btfids code path in resolve_btfids as a drop-in replacement for: ${OBJCOPY} --update-section .BTF_ids=${btf_ids} ${elf} Which works specifically for .BTF_ids section: ${RESOLVE_BTFIDS} --patch_btfids ${btf_ids} ${elf} This feature in resolve_btfids can be removed at some point in the future, when llvm-objcopy with a relevant bugfix becomes common. [1] https://lore.kernel.org/bpf/20251219181321.1283664-1-ihor.solodrai@linux.dev/ [2] https://lore.kernel.org/bpf/20251224005752.201911-1-ihor.solodrai@linux.dev/ [3] https://github.com/llvm/llvm-project/issues/168060#issuecomment-3533552952 Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Link: https://lore.kernel.org/r/20251231012558.1699758-1-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Recent changes in BTF generation [1] rely on ${OBJCOPY} command to
update .BTF_ids section data in target ELF files.

This exposed a bug in llvm-objcopy --update-section code path, that
may lead to corruption of a target ELF file. Specifically, because of
the bug st_shndx of some symbols may be (incorrectly) set to 0xffff
(SHN_XINDEX) [2][3].

While there is a pending fix for LLVM, it'll take some time before it
lands (likely in 22.x). And the kernel build must keep working with
older LLVM toolchains in the foreseeable future.

Using GNU objcopy for .BTF_ids update would work, but it would require
changes to LLVM-based build process, likely breaking existing build
environments as discussed in [2].

To work around llvm-objcopy bug, implement --patch_btfids code path in
resolve_btfids as a drop-in replacement for:

    ${OBJCOPY} --update-section .BTF_ids=${btf_ids} ${elf}

Which works specifically for .BTF_ids section:

    ${RESOLVE_BTFIDS} --patch_btfids ${btf_ids} ${elf}

This feature in resolve_btfids can be removed at some point in the
future, when llvm-objcopy with a relevant bugfix becomes common.

[1] https://lore.kernel.org/bpf/20251219181321.1283664-1-ihor.solodrai@linux.dev/
[2] https://lore.kernel.org/bpf/20251224005752.201911-1-ihor.solodrai@linux.dev/
[3] https://github.com/llvm/llvm-project/issues/168060#issuecomment-3533552952

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20251231012558.1699758-1-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
resolve_btfids: Change in-place update with raw binary output 2025-12-19T18:55:40+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2025-12-19T18:18:25+00:00 522397d05e7d4a7c30b91841492360336b24f833 Currently resolve_btfids updates .BTF_ids section of an ELF file in-place, based on the contents of provided BTF, usually within the same input file, and optionally a BTF base. Change resolve_btfids behavior to enable BTF transformations as part of its main operation. To achieve this, in-place ELF write in resolve_btfids is replaced with generation of the following binaries: * ${1}.BTF with .BTF section data * ${1}.BTF_ids with .BTF_ids section data if it existed in ${1} * ${1}.BTF.base with .BTF.base section data for out-of-tree modules The execution of resolve_btfids and consumption of its output is orchestrated by scripts/gen-btf.sh introduced in this patch. The motivation for emitting binary data is that it allows simplifying resolve_btfids implementation by delegating ELF update to the $OBJCOPY tool [1], which is already widely used across the codebase. There are two distinct paths for BTF generation and resolve_btfids application in the kernel build: for vmlinux and for kernel modules. For the vmlinux binary a .BTF section is added in a roundabout way to ensure correct linking. The patch doesn't change this approach, only the implementation is a little different. Before this patch it worked as follows: * pahole consumed .tmp_vmlinux1 [2] and added .BTF section with llvm-objcopy [3] to it * then everything except the .BTF section was stripped from .tmp_vmlinux1 into a .tmp_vmlinux1.bpf.o object [2], later linked into vmlinux * resolve_btfids was executed later on vmlinux.unstripped [4], updating it in-place After this patch gen-btf.sh implements the following: * pahole consumes .tmp_vmlinux1 and produces a *detached* file with raw BTF data * resolve_btfids consumes .tmp_vmlinux1 and detached BTF to produce (potentially modified) .BTF, and .BTF_ids sections data * a .tmp_vmlinux1.bpf.o object is then produced with objcopy copying BTF output of resolve_btfids * .BTF_ids data gets embedded into vmlinux.unstripped in link-vmlinux.sh by objcopy --update-section For kernel modules, creating a special .bpf.o file is not necessary, and so embedding of sections data produced by resolve_btfids is straightforward with objcopy. With this patch an ELF file becomes effectively read-only within resolve_btfids, which allows deleting elf_update() call and satellite code (like compressed_section_fix [5]). Endianness handling of .BTF_ids data is also changed. Previously the "flags" part of the section was bswapped in sets_patch() [6], and then Elf_Type was modified before elf_update() to signal to libelf that bswap may be necessary. With this patch we explicitly bswap entire data buffer on load and on dump. [1] https://lore.kernel.org/bpf/131b4190-9c49-4f79-a99d-c00fac97fa44@linux.dev/ [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.18#n110 [3] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/tree/btf_encoder.c?h=v1.31#n1803 [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.18#n284 [5] https://lore.kernel.org/bpf/20200819092342.259004-1-jolsa@kernel.org/ [6] https://lore.kernel.org/bpf/cover.1707223196.git.vmalik@redhat.com/ Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20251219181825.1289460-3-ihor.solodrai@linux.dev 
Currently resolve_btfids updates .BTF_ids section of an ELF file
in-place, based on the contents of provided BTF, usually within the
same input file, and optionally a BTF base.

Change resolve_btfids behavior to enable BTF transformations as part
of its main operation. To achieve this, in-place ELF write in
resolve_btfids is replaced with generation of the following binaries:
  * ${1}.BTF with .BTF section data
  * ${1}.BTF_ids with .BTF_ids section data if it existed in ${1}
  * ${1}.BTF.base with .BTF.base section data for out-of-tree modules

The execution of resolve_btfids and consumption of its output is
orchestrated by scripts/gen-btf.sh introduced in this patch.

The motivation for emitting binary data is that it allows simplifying
resolve_btfids implementation by delegating ELF update to the $OBJCOPY
tool [1], which is already widely used across the codebase.

There are two distinct paths for BTF generation and resolve_btfids
application in the kernel build: for vmlinux and for kernel modules.

For the vmlinux binary a .BTF section is added in a roundabout way to
ensure correct linking. The patch doesn't change this approach, only
the implementation is a little different.

Before this patch it worked as follows:

  * pahole consumed .tmp_vmlinux1 [2] and added .BTF section with
    llvm-objcopy [3] to it
  * then everything except the .BTF section was stripped from .tmp_vmlinux1
    into a .tmp_vmlinux1.bpf.o object [2], later linked into vmlinux
  * resolve_btfids was executed later on vmlinux.unstripped [4],
    updating it in-place

After this patch gen-btf.sh implements the following:

  * pahole consumes .tmp_vmlinux1 and produces a *detached* file with
    raw BTF data
  * resolve_btfids consumes .tmp_vmlinux1 and detached BTF to produce
    (potentially modified) .BTF, and .BTF_ids sections data
  * a .tmp_vmlinux1.bpf.o object is then produced with objcopy copying
    BTF output of resolve_btfids
  * .BTF_ids data gets embedded into vmlinux.unstripped in
    link-vmlinux.sh by objcopy --update-section

For kernel modules, creating a special .bpf.o file is not necessary,
and so embedding of sections data produced by resolve_btfids is
straightforward with objcopy.

With this patch an ELF file becomes effectively read-only within
resolve_btfids, which allows deleting elf_update() call and satellite
code (like compressed_section_fix [5]).

Endianness handling of .BTF_ids data is also changed. Previously the
"flags" part of the section was bswapped in sets_patch() [6], and then
Elf_Type was modified before elf_update() to signal to libelf that
bswap may be necessary. With this patch we explicitly bswap entire
data buffer on load and on dump.

[1] https://lore.kernel.org/bpf/131b4190-9c49-4f79-a99d-c00fac97fa44@linux.dev/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.18#n110
[3] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/tree/btf_encoder.c?h=v1.31#n1803
[4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.18#n284
[5] https://lore.kernel.org/bpf/20200819092342.259004-1-jolsa@kernel.org/
[6] https://lore.kernel.org/bpf/cover.1707223196.git.vmalik@redhat.com/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251219181825.1289460-3-ihor.solodrai@linux.dev
resolve_btfids: Always build with -Wall -Werror 2025-12-19T18:55:40+00:00 Ihor Solodrai ihor.solodrai@linux.dev 2025-12-19T18:13:17+00:00 fb348d4fdf5ec08aea8b1f686136584f758e4364 resolve_btfids builds without compiler warnings currently, so let's enforce this for future changes with '-Wall -Werror' flags [1]. [1] https://lore.kernel.org/bpf/1957a60b-6c45-42a7-b525-a6e335a735ff@linux.dev/ Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20251219181321.1283664-5-ihor.solodrai@linux.dev 
resolve_btfids builds without compiler warnings currently, so let's
enforce this for future changes with '-Wall -Werror' flags [1].

[1] https://lore.kernel.org/bpf/1957a60b-6c45-42a7-b525-a6e335a735ff@linux.dev/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-5-ihor.solodrai@linux.dev