glibc ≥ 2.42 (GCC 15) defaults to -std=gnu23, which promotes -Wdiscarded-qualifiers to an error in the default hardening flags of Fedora Rawhide, Arch Linux, openSUSE Tumbleweed, Gentoo, etc. In C23, strstr() and strchr() return "const char *" in most cases, making previous implicit casts invalid. This breaks the build of tools/bpf/resolve_btfids on pristine upstream kernel when using GCC 15 + glibc 2.42+. Fix the three remaining instances with explicit casts. No functional changes. Link: https://bugzilla.redhat.com/show_bug.cgi?id=2417601 Suggested-by: Florian Weimer Signed-off-by: Mikhail Gavrilov --- v2: - Declare `res` as `const char *` — never modified. - Keep `sym_sfx` as `char *` and cast — it is advanced in the loop. - Cast `next_path` — declared as `char *` earlier in the function. Changing it to const would require refactoring the whole function, which is not justified for a tools/ file. --- tools/lib/bpf/libbpf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index dd3b2f57082d..22ccd50e9978 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) @@ -11576,7 +11576,7 @@ static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type, */ char sym_trim[256], *psym_trim = sym_trim, *sym_sfx; - if (!(sym_sfx = strstr(sym_name, ".llvm."))) + if (!(sym_sfx = (char *)strstr(sym_name, ".llvm."))) /* needs mutation */ return 0; /* psym_trim vs sym_trim dance is done to avoid pointer vs array @@ -12164,7 +12164,7 @@ static int resolve_full_path(const char *file, char *result, size_t result_sz) if (s[0] == ':') s++; - next_path = strchr(s, ':'); + next_path = (char *)strchr(s, ':'); /* declared as char * above */ seg_len = next_path ? next_path - s : strlen(s); if (!seg_len) continue; -- 2.52.0