From 0a3798eaed3f45a93463414c0f4752b54e8978de Mon Sep 17 00:00:00 2001 From: He Zhe Date: Wed, 13 May 2026 10:33:18 +0800 Subject: [PATCH] bpftool-native: Fix -Wdiscarded-qualifiers errors for glibc 2.42+ MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Backport a patch from kernel to fix the following build errors. bbpf.c: In function ‘kallsyms_cb’: | libbpf.c:8192:13: error: assignment discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers] | 8192 | res = strstr(sym_name, ".llvm."); | | ^ | libbpf.c: In function ‘avail_kallsyms_cb’: | libbpf.c:11497:31: error: assignment discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers] | 11497 | if (!(sym_sfx = strstr(sym_name, ".llvm."))) | | ^ | libbpf.c: In function ‘resolve_full_path’: | libbpf.c:12085:35: error: assignment discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers] | 12085 | next_path = strchr(s, ':'); | | Signed-off-by: He Zhe Signed-off-by: Khem Raj --- .../bpftool/bpftool-native_6.16.bb | 5 +- ...-Fix-Wdiscarded-qualifiers-under-C23.patch | 69 +++++++++++++++++++ 2 files changed, 73 insertions(+), 1 deletion(-) create mode 100644 meta-oe/recipes-kernel/bpftool/bpftool/0001-libbpf-Fix-Wdiscarded-qualifiers-under-C23.patch diff --git a/meta-oe/recipes-kernel/bpftool/bpftool-native_6.16.bb b/meta-oe/recipes-kernel/bpftool/bpftool-native_6.16.bb index fe3ad6138e..edc635517a 100644 --- a/meta-oe/recipes-kernel/bpftool/bpftool-native_6.16.bb +++ b/meta-oe/recipes-kernel/bpftool/bpftool-native_6.16.bb @@ -9,7 +9,10 @@ DEPENDS = "binutils-native elfutils-native" inherit native bash-completion -SRC_URI = "${KERNELORG_MIRROR}/linux/kernel/v6.x/linux-${PV}.tar.xz" +SRC_URI = "\ + ${KERNELORG_MIRROR}/linux/kernel/v6.x/linux-${PV}.tar.xz \ + file://0001-libbpf-Fix-Wdiscarded-qualifiers-under-C23.patch \ +" SRC_URI[sha256sum] = "1a4be2fe6b5246aa4ac8987a8a4af34c42a8dd7d08b46ab48516bcc1befbcd83" S = "${UNPACKDIR}/linux-${PV}" diff --git a/meta-oe/recipes-kernel/bpftool/bpftool/0001-libbpf-Fix-Wdiscarded-qualifiers-under-C23.patch b/meta-oe/recipes-kernel/bpftool/bpftool/0001-libbpf-Fix-Wdiscarded-qualifiers-under-C23.patch new file mode 100644 index 0000000000..4726727c3d --- /dev/null +++ b/meta-oe/recipes-kernel/bpftool/bpftool/0001-libbpf-Fix-Wdiscarded-qualifiers-under-C23.patch @@ -0,0 +1,69 @@ +From ab21cf885fb2af179c44d8beeabd716133b9385d Mon Sep 17 00:00:00 2001 +From: Mikhail Gavrilov +Date: Sat, 6 Dec 2025 14:28:25 +0500 +Subject: [PATCH] libbpf: Fix -Wdiscarded-qualifiers under C23 +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +commit d70f79fef65810faf64dbae1f3a1b5623cdb2345 upstream. + +glibc ≥ 2.42 (GCC 15) defaults to -std=gnu23, which promotes +-Wdiscarded-qualifiers to an error. + +In C23, strstr() and strchr() return "const char *". + +Change variable types to const char * where the pointers are never +modified (res, sym_sfx, next_path). + +Suggested-by: Florian Weimer +Suggested-by: Andrii Nakryiko +Signed-off-by: Mikhail Gavrilov +Link: https://lore.kernel.org/r/20251206092825.1471385-1-mikhail.v.gavrilov@gmail.com +Signed-off-by: Alexei Starovoitov +[ shung-hsi.yu: needed to fix kernel build failure due to libbpf since glibc + 2.43+ (which adds 'const' qualifier to strstr) ] +Signed-off-by: Shung-Hsi Yu +Signed-off-by: Greg Kroah-Hartman + +Upstream-Status: Backport [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.18.y&id=ab21cf885fb2af179c44d8beeabd716133b9385d] +Signed-off-by: He Zhe +--- + tools/lib/bpf/libbpf.c | 7 ++++--- + 1 file changed, 4 insertions(+), 3 deletions(-) + +diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c +index dd3b2f57082d..9c98c6adb6d0 100644 +--- a/tools/lib/bpf/libbpf.c ++++ b/tools/lib/bpf/libbpf.c +@@ -8245,7 +8245,7 @@ static int kallsyms_cb(unsigned long long sym_addr, char sym_type, + struct bpf_object *obj = ctx; + const struct btf_type *t; + struct extern_desc *ext; +- char *res; ++ const char *res; + + res = strstr(sym_name, ".llvm."); + if (sym_type == 'd' && res) +@@ -11574,7 +11574,8 @@ static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type, + * + * [0] fb6a421fb615 ("kallsyms: Match symbols exactly with CONFIG_LTO_CLANG") + */ +- char sym_trim[256], *psym_trim = sym_trim, *sym_sfx; ++ char sym_trim[256], *psym_trim = sym_trim; ++ const char *sym_sfx; + + if (!(sym_sfx = strstr(sym_name, ".llvm."))) + return 0; +@@ -12159,7 +12160,7 @@ static int resolve_full_path(const char *file, char *result, size_t result_sz) + if (!search_paths[i]) + continue; + for (s = search_paths[i]; s != NULL; s = strchr(s, ':')) { +- char *next_path; ++ const char *next_path; + int seg_len; + + if (s[0] == ':') +-- +2.34.1 +