[PATCH 6.6 065/166] objtool: Remove max symbol name length limitation

Greg Kroah-Hartman
2026-04-24T13:36:15Z

From: Aaron Plattner <aplattner@nvidia.com>

[ Upstream commit f404a58dcf0c862b05602f641ce5fdd8b98fbc3a ]

If one of the symbols processed by read_symbols() happens to have a
.cold variant with a name longer than objtool's MAX_NAME_LEN limit, the
build fails.

Avoid this problem by just using strndup() to copy the parent function's
name, rather than strncpy()ing it onto the stack.

Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Link: https://lore.kernel.org/r/41e94cfea1d9131b758dd637fecdeacd459d4584.1696355111.git.aplattner@nvidia.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/objtool/elf.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 797507a90251b..19021f9755ac7 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -22,8 +22,6 @@
#include <objtool/elf.h>
#include <objtool/warn.h>

-#define MAX_NAME_LEN 128
-
static inline u32 str_hash(const char *str)
{
return jhash(str, strlen(str), 0);
@@ -515,7 +513,7 @@ static int read_symbols(struct elf *elf)
/* Create parent/child links for any cold subfunctions */
list_for_each_entry(sec, &elf->sections, list) {
sec_for_each_sym(sec, sym) {
- char pname[MAX_NAME_LEN + 1];
+ char *pname;
size_t pnamelen;
if (sym->type != STT_FUNC)
continue;
@@ -531,15 +529,15 @@ static int read_symbols(struct elf *elf)
continue;

pnamelen = coldstr - sym->name;
- if (pnamelen > MAX_NAME_LEN) {
- WARN("%s(): parent function name exceeds maximum length of %d characters",
- sym->name, MAX_NAME_LEN);
+ pname = strndup(sym->name, pnamelen);
+ if (!pname) {
+ WARN("%s(): failed to allocate memory",
+ sym->name);
return -1;
}

- strncpy(pname, sym->name, pnamelen);
- pname[pnamelen] = '\0';
pfunc = find_symbol_by_name(elf, pname);
+ free(pname);

if (!pfunc) {
WARN("%s(): can't find parent function",
--
2.53.0