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objtool: Remove max symbol name length limitation

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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>
This commit is contained in:
Aaron Plattner 2023-10-04 17:08:19 -07:00 committed by Josh Poimboeuf
parent e959c279d3
commit f404a58dcf
1 changed files with 6 additions and 8 deletions
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14
tools/objtool/elf.c
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@ -22,8 +22,6 @@
#include <objtool/elf.h> #include <objtool/elf.h>
#include <objtool/warn.h> #include <objtool/warn.h>
#define MAX_NAME_LEN 128
static inline u32 str_hash(const char *str) static inline u32 str_hash(const char *str)
{ {
return jhash(str, strlen(str), 0); 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 */ /* Create parent/child links for any cold subfunctions */
list_for_each_entry(sec, &elf->sections, list) { list_for_each_entry(sec, &elf->sections, list) {
sec_for_each_sym(sec, sym) { sec_for_each_sym(sec, sym) {
char pname[MAX_NAME_LEN + 1]; char *pname;
size_t pnamelen; size_t pnamelen;
if (sym->type != STT_FUNC) if (sym->type != STT_FUNC)
continue; continue;
@ -531,15 +529,15 @@ static int read_symbols(struct elf *elf)
continue; continue;
pnamelen = coldstr - sym->name; pnamelen = coldstr - sym->name;
if (pnamelen > MAX_NAME_LEN) { pname = strndup(sym->name, pnamelen);
WARN("%s(): parent function name exceeds maximum length of %d characters", if (!pname) {
sym->name, MAX_NAME_LEN); WARN("%s(): failed to allocate memory",
sym->name);
return -1; return -1;
} }
strncpy(pname, sym->name, pnamelen);
pname[pnamelen] = '\0';
pfunc = find_symbol_by_name(elf, pname); pfunc = find_symbol_by_name(elf, pname);
free(pname);
if (!pfunc) { if (!pfunc) {
WARN("%s(): can't find parent function", WARN("%s(): can't find parent function",