[PATCH v3] tools/lib/bpf: fix -Wdiscarded-qualifiers under C23
From: Mikhail Gavrilov <hidden>
Date: 2025-12-06 09:29:02
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
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 <redacted> Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Mikhail Gavrilov <redacted> --- v2: use const char * where possible v3: split declaration of sym_sfx — it is only read, never written --- 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 3dc8a8078815..f4dfd23148a5 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c@@ -8484,7 +8484,7 @@ 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)
@@ -11818,7 +11818,8 @@ 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;
@@ -12401,7 +12402,7 @@ 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] == ':')
--
2.52.0