From: zhidao su Date: Tue, 24 Mar 2026 18:47:18 +0000 (+0800) Subject: docs: Raise minimum pahole version to 1.26 for KF_IMPLICIT_ARGS kfuncs X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9edd04c4189e047d4b4f6efd1255e2a32cb167b8;p=thirdparty%2Flinux.git docs: Raise minimum pahole version to 1.26 for KF_IMPLICIT_ARGS kfuncs Since Linux 7.0, kfuncs annotated with KF_IMPLICIT_ARGS require pahole v1.26 or later. Without it, such kfuncs will have incorrect BTF prototypes in vmlinux, causing BPF programs to fail to load with a "func_proto incompatible with vmlinux" error. Many sched_ext kfuncs are affected (e.g. scx_bpf_create_dsq, scx_bpf_kick_cpu). The root cause: scripts/Makefile.btf passes --btf_features=decl_tag_kfuncs to pahole only when pahole >= 1.26. Without that flag, pahole emits no DECL_TAG BTF entries for __bpf_kfunc-annotated functions. As a result, resolve_btfids/main.c::collect_kfuncs() finds no bpf_kfunc DECL_TAGs, short-circuits at line 1002, and btf2btf() never creates the _impl variants or strips the implicit 'aux' argument from the visible proto. The vmlinux BTF retains the 3-param prototype while BPF programs declare the 2-param version, triggering the mismatch. Raise the minimum version in the requirements table from 1.22 to 1.26 and add a note explaining the failure mode, so users understand why their BPF programs fail on distributions shipping pahole v1.25 (e.g. Ubuntu 24.04 LTS). Suggested-by: Jonathan Corbet Signed-off-by: zhidao su Signed-off-by: Tejun Heo --- diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index 6b373e1935485..02068d72a101e 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -38,7 +38,7 @@ bash 4.2 bash --version binutils 2.30 ld -v flex 2.5.35 flex --version bison 2.0 bison --version -pahole 1.22 pahole --version +pahole 1.26 pahole --version util-linux 2.10o mount --version kmod 13 depmod -V e2fsprogs 1.41.4 e2fsck -V @@ -145,6 +145,11 @@ Since Linux 5.2, if CONFIG_DEBUG_INFO_BTF is selected, the build system generates BTF (BPF Type Format) from DWARF in vmlinux, a bit later from kernel modules as well. This requires pahole v1.22 or later. +Since Linux 7.0, kfuncs annotated with KF_IMPLICIT_ARGS require pahole v1.26 +or later. Without it, such kfuncs will have incorrect BTF prototypes in +vmlinux, causing BPF programs to fail to load with a "func_proto incompatible +with vmlinux" error. Many sched_ext kfuncs are affected. + It is found in the 'dwarves' or 'pahole' distro packages or from https://fedorapeople.org/~acme/dwarves/.