[tip:core/urgent] objtool: Fix double-free in .cold detection error path

[tip-bot for Artem Savkov]

Commit-ID:  0b9301fb632f7111a3293a30cc5b20f1b82ed08d
Gitweb:     https://git.kernel.org/tip/0b9301fb632f7111a3293a30cc5b20f1b82ed08d
Author:     Artem Savkov <asavkov@xxxxxxxxxx>
AuthorDate: Tue, 20 Nov 2018 11:52:15 -0600
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 20 Nov 2018 18:59:00 +0100

objtool: Fix double-free in .cold detection error path

If read_symbols() fails during second list traversal (the one dealing
with ".cold" subfunctions) it frees the symbol, but never deletes it
from the list/hash_table resulting in symbol being freed again in
elf_close(). Fix it by just returning an error, leaving cleanup to
elf_close().

Signed-off-by: Artem Savkov <asavkov@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
Link: http://lkml.kernel.org/r/beac5a9b7da9e8be90223459dcbe07766ae437dd.1542736240.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 tools/objtool/elf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6dbb9fae0f9d..e7a7ac40e045 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -312,7 +312,7 @@ static int read_symbols(struct elf *elf)
 			if (!pfunc) {
 				WARN("%s(): can't find parent function",
 				     sym->name);
-				goto err;
+				return -1;
 			}
 
 			sym->pfunc = pfunc;