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Date: Wed, 15 Apr 2020 14:04:43 -0700
From: Kristen Carlson Accardi <kristen@...ux.intel.com>
To: keescook@...omium.org,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	hpa@...or.com,
	Josh Poimboeuf <jpoimboe@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>
Cc: arjan@...ux.intel.com,
	x86@...nel.org,
	linux-kernel@...r.kernel.org,
	kernel-hardening@...ts.openwall.com,
	rick.p.edgecomb@...el.com
Subject: [PATCH 1/9] 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.

Signed-off-by: Kristen Carlson Accardi <kristen@...ux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 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 09ddc8f1def3..2aa40f344392 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

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