Skip to content

Commit

Permalink
btf, scripts: Exclude Rust CUs with pahole
Browse files Browse the repository at this point in the history
Version 1.24 of pahole has the capability to exclude compilation units (CUs)
of specific languages [1] [2]. Rust, as of writing, is not currently supported
by pahole and if it's used with a build that has BTF debugging enabled it
results in malformed kernel and module binaries [3]. So it's better for pahole
to exclude Rust CUs until support for it arrives.

Co-developed-by: Eric Curtin <ecurtin@redhat.com>
Signed-off-by: Eric Curtin <ecurtin@redhat.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
Link: #735 [3]
Link: https://lore.kernel.org/bpf/20230111152050.559334-1-yakoyoku@gmail.com
  • Loading branch information
YakoYakoYokuYoku authored and borkmann committed Jan 17, 2023
1 parent dfff86f commit c117797
Show file tree
Hide file tree
Showing 3 changed files with 14 additions and 1 deletion.
2 changes: 1 addition & 1 deletion init/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -1935,7 +1935,7 @@ config RUST
depends on !MODVERSIONS
depends on !GCC_PLUGINS
depends on !RANDSTRUCT
depends on !DEBUG_INFO_BTF
depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
select CONSTRUCTORS
help
Enables Rust support in the kernel.
Expand Down
9 changes: 9 additions & 0 deletions lib/Kconfig.debug
Original file line number Diff line number Diff line change
Expand Up @@ -389,6 +389,15 @@ config PAHOLE_HAS_BTF_TAG
btf_decl_tag) or not. Currently only clang compiler implements
these attributes, so make the config depend on CC_IS_CLANG.

config PAHOLE_HAS_LANG_EXCLUDE
def_bool PAHOLE_VERSION >= 124
help
Support for the --lang_exclude flag which makes pahole exclude
compilation units from the supplied language. Used in Kbuild to
omit Rust CUs which are not supported in version 1.24 of pahole,
otherwise it would emit malformed kernel and module binaries when
using DEBUG_INFO_BTF_MODULES.

config DEBUG_INFO_BTF_MODULES
def_bool y
depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
Expand Down
4 changes: 4 additions & 0 deletions scripts/pahole-flags.sh
Original file line number Diff line number Diff line change
Expand Up @@ -19,5 +19,9 @@ fi
if [ "${pahole_ver}" -ge "122" ]; then
extra_paholeopt="${extra_paholeopt} -j"
fi
if [ "${pahole_ver}" -ge "124" ]; then
# see PAHOLE_HAS_LANG_EXCLUDE
extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
fi

echo ${extra_paholeopt}

0 comments on commit c117797

Please sign in to comment.