linux-kernel - [tip:core/urgent] objtool: Do frame pointer check before dead end check

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Message-ID: <tip-c9bab22bc449ad2496a6bbbf68acc711d9c5301c@git.kernel.org>
Date:   Thu, 18 Jul 2019 12:18:28 -0700
From:   tip-bot for Josh Poimboeuf <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, linux-kernel@...r.kernel.org, peterz@...radead.org,
        ndesaulniers@...gle.com, tglx@...utronix.de, jpoimboe@...hat.com,
        mingo@...nel.org
Subject: [tip:core/urgent] objtool: Do frame pointer check before dead end
 check

Commit-ID:  c9bab22bc449ad2496a6bbbf68acc711d9c5301c
Gitweb:     https://git.kernel.org/tip/c9bab22bc449ad2496a6bbbf68acc711d9c5301c
Author:     Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate: Wed, 17 Jul 2019 20:36:51 -0500
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 18 Jul 2019 21:01:08 +0200

objtool: Do frame pointer check before dead end check

Even calls to __noreturn functions need the frame pointer setup first.
Such functions often dump the stack.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Nick Desaulniers <ndesaulniers@...gle.com>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/aed62fbd60e239280218be623f751a433658e896.1563413318.git.jpoimboe@redhat.com

---
 tools/objtool/check.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d9d1c9b54947..0d2a8e54a82e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -133,6 +133,9 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"rewind_stack_do_exit",
 	};
 
+	if (!func)
+		return false;
+
 	if (func->bind == STB_WEAK)
 		return false;
 
@@ -2071,19 +2074,16 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 			if (ret)
 				return ret;
 
-			if (insn->type == INSN_CALL) {
-				if (is_fentry_call(insn))
-					break;
-
-				if (dead_end_function(file, insn->call_dest))
-					return 0;
-			}
-
-			if (!no_fp && func && !has_valid_stack_frame(&state)) {
+			if (!no_fp && func && !is_fentry_call(insn) &&
+			    !has_valid_stack_frame(&state)) {
 				WARN_FUNC("call without frame pointer save/setup",
 					  sec, insn->offset);
 				return 1;
 			}
+
+			if (dead_end_function(file, insn->call_dest))
+				return 0;
+
 			break;
 
 		case INSN_JUMP_CONDITIONAL: