From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 27 Mar 2020 15:28:40 +0000
Subject: objtool: Clean instruction state before each function validation
Git-commit: 0699e551af268c9841a205a3e90dc1615fb63d84
Patch-mainline: v5.8-rc1
References: bsc#1169514

When a function fails its validation, it might leave a stale state
that will be used for the validation of other functions. That would
cause false warnings on potentially valid functions.

Reset the instruction state before the validation of each individual
function.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
 tools/objtool/check.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2143,13 +2143,6 @@ static int validate_functions(struct obj
 	struct insn_state state;
 	int ret, warnings = 0;
 
-	clear_insn_state(&state);
-
-	state.cfa = initial_func_cfi.cfa;
-	memcpy(&state.regs, &initial_func_cfi.regs,
-	       CFI_NUM_REGS * sizeof(struct cfi_reg));
-	state.stack_size = initial_func_cfi.cfa.offset;
-
 	for_each_sec(file, sec) {
 		list_for_each_entry(func, &sec->symbol_list, list) {
 			if (func->type != STT_FUNC || func->pfunc != func)
@@ -2159,6 +2152,12 @@ static int validate_functions(struct obj
 			if (!insn || insn->ignore || insn->visited)
 				continue;
 
+			clear_insn_state(&state);
+			state.cfa = initial_func_cfi.cfa;
+			memcpy(&state.regs, &initial_func_cfi.regs,
+			       CFI_NUM_REGS * sizeof(struct cfi_reg));
+			state.stack_size = initial_func_cfi.cfa.offset;
+
 			ret = validate_branch(file, func, insn, state);
 			if (ret && backtrace)
 				BT_FUNC("<=== (func)", insn);