[PATCH 01/48] objtool/klp: Fix is_uncorrelated_static_local() for Clang

Josh Poimboeuf
2026-04-23T04:04:24Z

From: Joe Lawrence <joe.lawrence@redhat.com>

For naming function-local static locals, GCC uses .<id>, e.g.
__already_done.15, while Clang uses <func>. with optional .<id>,
e.g. create_worker.__already_done.111

The existing is_uncorrelated_static_local() check only matches the GCC
convention where the variable name is a prefix. Handle both cases by
checking for a prefix match (GCC) and by checking after the first dot
separator (Clang).

Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/klp-diff.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 0b0d1503851f..b1b068e9b4c7 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -242,16 +242,17 @@ static struct symbol *next_file_symbol(struct elf *elf, struct symbol *sym)
static bool is_uncorrelated_static_local(struct symbol *sym)
{
static const char * const vars[] = {
- "__already_done.",
- "__func__.",
- "__key.",
- "__warned.",
- "_entry.",
- "_entry_ptr.",
- "_rs.",
- "descriptor.",
- "CSWTCH.",
+ "__already_done",
+ "__func__",
+ "__key",
+ "__warned",
+ "_entry",
+ "_entry_ptr",
+ "_rs",
+ "descriptor",
+ "CSWTCH",
};
+ const char *dot;

if (!is_object_sym(sym) || !is_local_sym(sym))
return false;
@@ -259,8 +260,20 @@ static bool is_uncorrelated_static_local(struct symbol *sym)
if (!strcmp(sym->sec->name, ".data.once"))
return true;

+ dot = strchr(sym->name, '.');
+ if (!dot)
+ return false;
+
for (int i = 0; i < ARRAY_SIZE(vars); i++) {
- if (strstarts(sym->name, vars[i]))
+ size_t len = strlen(vars[i]);
+
+ /* GCC: .<id> */
+ if (strstarts(sym->name, vars[i]) && (sym->name[len] == '.'))
+ return true;
+
+ /* Clang: <func>.[.<id>] */
+ if (strstarts(dot + 1, vars[i]) &&
+ (dot[1 + len] == '.' || dot[1 + len] == '\0'))
return true;
}

--
2.53.0