FAILED: patch "[PATCH] kbuild: userprogs: use correct linker when mixing clang and" failed to apply to 5.4-stable tree

FAILED: patch "[PATCH] kbuild: userprogs: use correct linker when mixing clang and" failed to apply to 5.4-stable tree

[gregkh]

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 936599ca514973d44a766b7376c6bbdc96b6a8cc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082106-cheer-train-f1fd@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 936599ca514973d44a766b7376c6bbdc96b6a8cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <thomas.weissschuh@linutronix.de>
Date: Mon, 28 Jul 2025 15:47:37 +0200
Subject: [PATCH] kbuild: userprogs: use correct linker when mixing clang and
 GNU ld
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The userprogs infrastructure does not expect clang being used with GNU ld
and in that case uses /usr/bin/ld for linking, not the configured $(LD).
This fallback is problematic as it will break when cross-compiling.
Mixing clang and GNU ld is used for example when building for SPARC64,
as ld.lld is not sufficient; see Documentation/kbuild/llvm.rst.

Relax the check around --ld-path so it gets used for all linkers.

Fixes: dfc1b168a8c4 ("kbuild: userprogs: use correct lld when linking through clang")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/Makefile b/Makefile
index ba0827a1fccd..f4009f7238c7 100644
--- a/Makefile
+++ b/Makefile
@@ -1134,7 +1134,7 @@ KBUILD_USERCFLAGS  += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD
 KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
 
 # userspace programs are linked via the compiler, use the correct linker
-ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_LD_IS_LLD),yy)
+ifdef CONFIG_CC_IS_CLANG
 KBUILD_USERLDFLAGS += --ld-path=$(LD)
 endif
 

Re: FAILED: patch "[PATCH] kbuild: userprogs: use correct linker when mixing clang and" failed to apply to 5.4-stable tree

[Nathan Chancellor]

On Thu, Aug 21, 2025 at 03:31:06PM +0200, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
...
> ------------------ original commit in Linus's tree ------------------
> 
> >From 936599ca514973d44a766b7376c6bbdc96b6a8cc Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <thomas.weissschuh@linutronix.de>
> Date: Mon, 28 Jul 2025 15:47:37 +0200
> Subject: [PATCH] kbuild: userprogs: use correct linker when mixing clang and
>  GNU ld
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
> 
> The userprogs infrastructure does not expect clang being used with GNU ld
> and in that case uses /usr/bin/ld for linking, not the configured $(LD).
> This fallback is problematic as it will break when cross-compiling.
> Mixing clang and GNU ld is used for example when building for SPARC64,
> as ld.lld is not sufficient; see Documentation/kbuild/llvm.rst.
> 
> Relax the check around --ld-path so it gets used for all linkers.
> 
> Fixes: dfc1b168a8c4 ("kbuild: userprogs: use correct lld when linking through clang")

While this commit is in 5.4, it does not actually do anything because
the userprogs infrastructure was not merged until 5.8 in commit
7f3a59db274c ("kbuild: add infrastructure to build userspace programs").
So I don't think it is worth applying this.

Cheers,
Nathan