[PATCH v3 1/2] objtool: fix failed cold symbol doublefree

From: Artem Savkov
Date: Mon Nov 12 2018 - 07:55:42 EST


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().

Fixes: 13810435b9a7 "objtool: Support GCC 8's cold subfunctions"
Signed-off-by: Artem Savkov <asavkov@xxxxxxxxxx>
---
tools/objtool/elf.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6dbb9fae0f9d..3decd43477df 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;
+ goto cold_err;
}

sym->pfunc = pfunc;
@@ -336,6 +336,9 @@ static int read_symbols(struct elf *elf)

return 0;

+cold_err:
+ list_del(&sym->list);
+ hash_del(&sym->hash);
err:
free(sym);
return -1;
--
2.17.2