[PATCH bpf-next v4 6/8] lib/Kconfig.debug: Set the minimum required pahole version to v1.22

Ihor Solodrai
2025-12-18T00:35:07Z

Subsequent patches in the series change vmlinux linking scripts to
unconditionally pass --btf_encode_detached to pahole, which was
introduced in v1.22 [1][2].

This change allows to remove PAHOLE_HAS_SPLIT_BTF Kconfig option and
other checks of older pahole versions.

[1] https://github.com/acmel/dwarves/releases/tag/v1.22
[2] https://lore.kernel.org/bpf/cbafbf4e-9073-4383-8ee6-1353f9e5869c@oracle.com/

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
Documentation/scheduler/sched-ext.rst | 1 -
lib/Kconfig.debug | 13 ++++---------
scripts/Makefile.btf | 9 +--------
tools/sched_ext/README.md | 1 -
4 files changed, 5 insertions(+), 19 deletions(-)

diff --git a/Documentation/scheduler/sched-ext.rst b/Documentation/scheduler/sched-ext.rst
index 404fe6126a76..9e2882d937b4 100644
--- a/Documentation/scheduler/sched-ext.rst
+++ b/Documentation/scheduler/sched-ext.rst
@@ -43,7 +43,6 @@ options should be enabled to use sched_ext:
CONFIG_DEBUG_INFO_BTF=y
CONFIG_BPF_JIT_ALWAYS_ON=y
CONFIG_BPF_JIT_DEFAULT_ON=y
- CONFIG_PAHOLE_HAS_SPLIT_BTF=y
CONFIG_PAHOLE_HAS_BTF_TAG=y

sched_ext is used only when the BPF scheduler is loaded and running.
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ba36939fda79..60281c4f9e99 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -388,18 +388,13 @@ config DEBUG_INFO_BTF
depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
depends on BPF_SYSCALL
- depends on PAHOLE_VERSION >= 116
- depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
+ depends on PAHOLE_VERSION >= 122
# pahole uses elfutils, which does not have support for Hexagon relocations
depends on !HEXAGON
help
Generate deduplicated BTF type information from DWARF debug info.
- Turning this on requires pahole v1.16 or later (v1.21 or later to
- support DWARF 5), which will convert DWARF type info into equivalent
- deduplicated BTF type info.
-
-config PAHOLE_HAS_SPLIT_BTF
- def_bool PAHOLE_VERSION >= 119
+ Turning this on requires pahole v1.22 or later, which will convert
+ DWARF type info into equivalent deduplicated BTF type info.

config PAHOLE_HAS_BTF_TAG
def_bool PAHOLE_VERSION >= 123
@@ -421,7 +416,7 @@ config PAHOLE_HAS_LANG_EXCLUDE
config DEBUG_INFO_BTF_MODULES
bool "Generate BTF type information for kernel modules"
default y
- depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
+ depends on DEBUG_INFO_BTF && MODULES
help
Generate compact split BTF type information for kernel modules.

diff --git a/scripts/Makefile.btf b/scripts/Makefile.btf
index db76335dd917..840a55de42da 100644
--- a/scripts/Makefile.btf
+++ b/scripts/Makefile.btf
@@ -7,14 +7,7 @@ JOBS := $(patsubst -j%,%,$(filter -j%,$(MAKEFLAGS)))

ifeq ($(call test-le, $(pahole-ver), 125),y)

-# pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars
-ifeq ($(call test-le, $(pahole-ver), 121),y)
-pahole-flags-$(call test-ge, $(pahole-ver), 118) += --skip_encoding_btf_vars
-endif
-
-pahole-flags-$(call test-ge, $(pahole-ver), 121) += --btf_gen_floats
-
-pahole-flags-$(call test-ge, $(pahole-ver), 122) += -j$(JOBS)
+pahole-flags-y += --btf_gen_floats -j$(JOBS)

pahole-flags-$(call test-ge, $(pahole-ver), 125) += --skip_encoding_btf_inconsistent_proto --btf_gen_optimized

diff --git a/tools/sched_ext/README.md b/tools/sched_ext/README.md
index 16a42e4060f6..56a9d1557ac4 100644
--- a/tools/sched_ext/README.md
+++ b/tools/sched_ext/README.md
@@ -65,7 +65,6 @@ It's also recommended that you also include the following Kconfig options:
```
CONFIG_BPF_JIT_ALWAYS_ON=y
CONFIG_BPF_JIT_DEFAULT_ON=y
-CONFIG_PAHOLE_HAS_SPLIT_BTF=y
CONFIG_PAHOLE_HAS_BTF_TAG=y
```

--
2.52.0