[tip: objtool/core] objtool: Do not assume order of parent/child functions

[tip-bot2 for Kristen Carlson Accardi]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     5920038dc2aa75b7aa3f5ca767b06a71c67cf897
Gitweb:        https://git.kernel.org/tip/5920038dc2aa75b7aa3f5ca767b06a71c67cf897
Author:        Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
AuthorDate:    Wed, 15 Apr 2020 14:04:43 -07:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Tue, 21 Apr 2020 18:50:26 -05:00

objtool: Do not assume order of parent/child functions

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.

This fixes an -ffunction-sections issue.

Signed-off-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
Signed-off-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 43748cb..03e542d 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -418,7 +418,13 @@ 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;