objtool: Fix segfault in .cold detection with -ffunction-sections
[sfrench/cifs-2.6.git] / tools / objtool / elf.c
index e7a7ac40e0454229cd82101735d361481d3fd7ce..b8f3cca8e58b4ec327876c7fd3173a4a3ae6c31d 100644 (file)
@@ -31,6 +31,8 @@
 #include "elf.h"
 #include "warn.h"
 
+#define MAX_NAME_LEN 128
+
 struct section *find_section_by_name(struct elf *elf, const char *name)
 {
        struct section *sec;
@@ -298,6 +300,8 @@ static int read_symbols(struct elf *elf)
        /* Create parent/child links for any cold subfunctions */
        list_for_each_entry(sec, &elf->sections, list) {
                list_for_each_entry(sym, &sec->symbol_list, list) {
+                       char pname[MAX_NAME_LEN + 1];
+                       size_t pnamelen;
                        if (sym->type != STT_FUNC)
                                continue;
                        sym->pfunc = sym->cfunc = sym;
@@ -305,9 +309,16 @@ static int read_symbols(struct elf *elf)
                        if (!coldstr)
                                continue;
 
-                       coldstr[0] = '\0';
-                       pfunc = find_symbol_by_name(elf, sym->name);
-                       coldstr[0] = '.';
+                       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);
+                               return -1;
+                       }
+
+                       strncpy(pname, sym->name, pnamelen);
+                       pname[pnamelen] = '\0';
+                       pfunc = find_symbol_by_name(elf, pname);
 
                        if (!pfunc) {
                                WARN("%s(): can't find parent function",