Re: [OE-core][scarthgap 04/11] dtc: backport fix for build with glibc-2.43

["Yoann Congal" <yoann.congal@smile.fr>]

On Mon Mar 30, 2026 at 12:46 AM CEST, Yoann Congal wrote:
> From: Martin Jansa <martin.jansa@gmail.com>
>
> glibc-2.43 isn't used in OE builds yet, but this fixes dtc-native:
> https://errors.yoctoproject.org/Errors/Details/903983/
>
> ../sources/dtc-1.7.2/libfdt/fdt_overlay.c: In function ‘overlay_fixup_phandle’:
> ../sources/dtc-1.7.2/libfdt/fdt_overlay.c:424:21: error: assignment discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
>   424 |                 sep = memchr(fixup_str, ':', fixup_len);
>       |                     ^
> ../sources/dtc-1.7.2/libfdt/fdt_overlay.c:434:21: error: assignment discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
>   434 |                 sep = memchr(name, ':', fixup_len);
>       |                     ^
> cc1: all warnings being treated as errors
>
> Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> [YC: upstream commit 28552a7b6c94060c7ab3899619ab8afb74124d02]
> Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
> ---

Hello Martin,

FYI, while it looked good, this patch and your whole series about glibc
2.43 support:
* [scarthgap 04/11] dtc: backport fix for build with glibc-2.43
* [scarthgap 05/11] pseudo: Add fix for glibc 2.43
* [scarthgap 06/11] yocto-uninative: Update to 5.0 for needed patchelf updates
* [scarthgap 07/11] yocto-uninative: Update to 5.1 for glibc 2.43
* [scarthgap 08/11] elfutils: don't add -Werror to avoid discarded-qualifiers
* [scarthgap 09/11] binutils: backport patch to fix build with glibc-2.43 on host
... will be put on hold until I can test it: So, not until Ubuntu 26.04
is released and the autobuilder gain an Ubuntu 26.04 worker (most likely
after Wrynose release).

Thanks!

Regards,

>  .../0001-Fix-discarded-const-qualifiers.patch | 85 +++++++++++++++++++
>  meta/recipes-kernel/dtc/dtc_1.7.0.bb          |  1 +
>  2 files changed, 86 insertions(+)
>  create mode 100644 meta/recipes-kernel/dtc/dtc/0001-Fix-discarded-const-qualifiers.patch
>
> diff --git a/meta/recipes-kernel/dtc/dtc/0001-Fix-discarded-const-qualifiers.patch b/meta/recipes-kernel/dtc/dtc/0001-Fix-discarded-const-qualifiers.patch
> new file mode 100644
> index 00000000000..c643410ae9b
> --- /dev/null
> +++ b/meta/recipes-kernel/dtc/dtc/0001-Fix-discarded-const-qualifiers.patch
> @@ -0,0 +1,85 @@
> +From 861cb43eb53afff83e28ba0e0f88ffa464ebe8ca Mon Sep 17 00:00:00 2001
> +From: Stephen Gallagher <sgallagh@redhat.com>
> +Date: Tue, 6 Jan 2026 14:19:30 -0500
> +Subject: [PATCH] Fix discarded const qualifiers
> +
> +It's unsafe to implicitly discard the const qualifier on a pointer. In
> +overlay_fixup_phandle(), this was probably just an oversight, and making
> +the "sep" variable a const char * is sufficient to fix it.
> +
> +In create_node(), however, the "p" variable is directly modifying the
> +buffer pointed to by "const char* node_name". To fix this, we need to
> +actually make a duplicate of the buffer and operate on that instead.
> +
> +This introduces a malloc()/free()  and an unbounded strdup() into the
> +operation, but fdtput isn't a long-running service and the node_name
> +argument comes directly from argv, so this shouldn't introduce a
> +significant performance impact.
> +
> +Signed-off-by: Stephen Gallagher <sgallagh@redhat.com>
> +Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> +Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
> +Upstream-Status: Backport [https://git.kernel.org/pub/scm/utils/dtc/dtc.git/commit/libfdt/fdt_overlay.c?h=main&id=9a1c801a1a3c102bf95c5339c9e985b26b823a21]
> +---
> + fdtput.c             | 8 +++++---
> + libfdt/fdt_overlay.c | 3 ++-
> + meson.build          | 3 ++-
> + 3 files changed, 9 insertions(+), 5 deletions(-)
> +
> +diff --git a/fdtput.c b/fdtput.c
> +index c2fecf4..8deec7e 100644
> +--- a/fdtput.c
> ++++ b/fdtput.c
> +@@ -230,19 +230,21 @@ static int create_paths(char **blob, const char *in_path)
> + static int create_node(char **blob, const char *node_name)
> + {
> + 	int node = 0;
> +-	char *p;
> ++	const char *p;
> ++	char *path = NULL;
> + 
> + 	p = strrchr(node_name, '/');
> + 	if (!p) {
> + 		report_error(node_name, -1, -FDT_ERR_BADPATH);
> + 		return -1;
> + 	}
> +-	*p = '\0';
> + 
> + 	*blob = realloc_node(*blob, p + 1);
> + 
> + 	if (p > node_name) {
> +-		node = fdt_path_offset(*blob, node_name);
> ++		path = xstrndup(node_name, (size_t)(p - node_name));
> ++		node = fdt_path_offset(*blob, path);
> ++		free(path);
> + 		if (node < 0) {
> + 			report_error(node_name, -1, node);
> + 			return -1;
> +diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c
> +index 5c0c398..75b0619 100644
> +--- a/libfdt/fdt_overlay.c
> ++++ b/libfdt/fdt_overlay.c
> +@@ -431,7 +431,8 @@ static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
> + 		const char *fixup_str = value;
> + 		uint32_t path_len, name_len;
> + 		uint32_t fixup_len;
> +-		char *sep, *endptr;
> ++		const char *sep;
> ++		char *endptr;
> + 		int poffset, ret;
> + 
> + 		fixup_end = memchr(value, '\0', len);
> +diff --git a/meson.build b/meson.build
> +index 8952e8a..ecb0ae0 100644
> +--- a/meson.build
> ++++ b/meson.build
> +@@ -14,7 +14,8 @@ add_project_arguments(
> +     '-Wstrict-prototypes',
> +     '-Wmissing-prototypes',
> +     '-Wredundant-decls',
> +-    '-Wshadow'
> ++    '-Wshadow',
> ++    '-Wdiscarded-qualifiers'
> +   ]),
> +   language: 'c'
> + )
> diff --git a/meta/recipes-kernel/dtc/dtc_1.7.0.bb b/meta/recipes-kernel/dtc/dtc_1.7.0.bb
> index 0702fc16dfa..a2f41197fda 100644
> --- a/meta/recipes-kernel/dtc/dtc_1.7.0.bb
> +++ b/meta/recipes-kernel/dtc/dtc_1.7.0.bb
> @@ -12,6 +12,7 @@ SRC_URI = " \
>      git://git.kernel.org/pub/scm/utils/dtc/dtc.git;branch=main;protocol=https \
>      file://0001-meson.build-bump-version-to-1.7.0.patch \
>      file://0002-meson-allow-building-from-shallow-clones.patch \
> +    file://0001-Fix-discarded-const-qualifiers.patch \
>  "
>  SRCREV = "039a99414e778332d8f9c04cbd3072e1dcc62798"
>  


-- 
Yoann Congal
Smile ECS