[PATCH v2 1/9] objtool: Do not assume order of parent/child functions

From: Kristen Carlson Accardi
Date: Thu May 21 2020 - 12:57:11 EST


If a .cold function is examined prior to it's parent, the link
to the parent/child function can be overwritten when the parent
is examined. Only update pfunc and cfunc if they were previously
nil to prevent this from happening.

Signed-off-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
tools/objtool/elf.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c4857fa3f1d1..b998c853a1f0 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -408,7 +408,13 @@ static int read_symbols(struct elf *elf)
size_t pnamelen;
if (sym->type != STT_FUNC)
continue;
- sym->pfunc = sym->cfunc = sym;
+
+ if (sym->pfunc == NULL)
+ sym->pfunc = sym;
+
+ if (sym->cfunc == NULL)
+ sym->cfunc = sym;
+
coldstr = strstr(sym->name, ".cold");
if (!coldstr)
continue;
--
2.20.1