linux-kernel - Re: [PATCH bpf-next v6 5/8] kbuild: Sync kconfig when PAHOLE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aUUDh1BkRcamDI9a@derry.ads.avm.de>
Date: Fri, 19 Dec 2025 08:49:27 +0100
From: Nicolas Schier <nsc@...nel.org>
To: Ihor Solodrai <ihor.solodrai@...ux.dev>
Cc: Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Nathan Chancellor <nathan@...nel.org>,
	Jonathan Corbet <corbet@....net>, Tejun Heo <tj@...nel.org>,
	David Vernet <void@...ifault.com>, Andrea Righi <arighi@...dia.com>,
	Changwoo Min <changwoo@...lia.com>, Shuah Khan <shuah@...nel.org>,
	Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
	Bill Wendling <morbo@...gle.com>,
	Justin Stitt <justinstitt@...gle.com>,
	Alan Maguire <alan.maguire@...cle.com>,
	Donglin Peng <dolinux.peng@...il.com>, bpf@...r.kernel.org,
	dwarves@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-kbuild@...r.kernel.org, sched-ext@...ts.linux.dev
Subject: Re: [PATCH bpf-next v6 5/8] kbuild: Sync kconfig when PAHOLE_VERSION
 changes

On Thu, Dec 18, 2025 at 06:00:03PM -0800, Ihor Solodrai wrote:
> This patch implements kconfig re-sync when the pahole version changes
> between builds, similar to how it happens for compiler version change
> via CC_VERSION_TEXT.
> 
> Define PAHOLE_VERSION in the top-level Makefile and export it for
> config builds. Set CONFIG_PAHOLE_VERSION default to the exported
> variable.
> 
> Kconfig records the PAHOLE_VERSION value in
> include/config/auto.conf.cmd [1].
> 
> The Makefile includes auto.conf.cmd, so if PAHOLE_VERSION changes
> between builds, make detects a dependency change and triggers
> syncconfig to update the kconfig [2].
> 
> For external module builds, add a warning message in the prepare
> target, similar to the existing compiler version mismatch warning.
> 
> Note that if pahole is not installed or available, PAHOLE_VERSION is
> set to 0 by pahole-version.sh, so the (un)installation of pahole is
> treated as a version change.
> 
> See previous discussions for context [3].
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/kconfig/preprocess.c?h=v6.18#n91
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile?h=v6.18#n815
> [3] https://lore.kernel.org/bpf/8f946abf-dd88-4fac-8bb4-84fcd8d81cf0@oracle.com/
> 
> Signed-off-by: Ihor Solodrai <ihor.solodrai@...ux.dev>
> ---
>  Makefile     | 9 ++++++++-
>  init/Kconfig | 2 +-
>  2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index e404e4767944..9b90a2a2218e 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -713,6 +713,7 @@ endif
>  # upgrade.
>  CC_VERSION_TEXT = $(subst $(pound),,$(shell LC_ALL=C $(CC) --version 2>/dev/null | head -n 1))
>  RUSTC_VERSION_TEXT = $(subst $(pound),,$(shell $(RUSTC) --version 2>/dev/null))
> +PAHOLE_VERSION = $(shell $(srctree)/scripts/pahole-version.sh $(PAHOLE))

As PAHOLE_VERSION is handled in the same way as CC_VERSION_TEXT and
RUSTC_VERSION_TEXT at line 736/737: could you please add it to the
comment above, too?

Patch looks good to me, thanks!

Reviewed-by: Nicolas Schier <nsc@...nel.org>
Tested-by: Nicolas Schier <nsc@...nel.org>