[GIT PULL] objtool fixes

[Ingo Molnar]

Linus,

Please pull the latest core-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core-urgent-for-linus

   # HEAD: 22566c1603030f0a036ad564634b064ad1a55db2 objtool: Fix segfault in .cold detection with -ffunction-sections

Two fixes for boundary conditions.

 Thanks,

	Ingo

------------------>
Artem Savkov (2):
      objtool: Fix double-free in .cold detection error path
      objtool: Fix segfault in .cold detection with -ffunction-sections


 tools/objtool/elf.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6dbb9fae0f9d..b8f3cca8e58b 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -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;
@@ -305,14 +309,21 @@ 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",
 				     sym->name);
-				goto err;
+				return -1;
 			}
 
 			sym->pfunc = pfunc;