objtool: Remove max symbol name length limitation [ 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. BUG=b/392934334 TEST=presubmit RELEASE_NOTE=None 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> Change-Id: I944b2a13f76dd0785fb2867e7f0d3366172b6eb4 Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/91728 Reviewed-by: Kevin Berry <kpberry@google.com> Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com> Reviewed-by: Arnav Kansal <rnv@google.com>

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 081befa..3d27983 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",