linux-kernel - [PATCH AUTOSEL 6.12 044/486] objtool: Properly disable uaccess validation

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Message-Id: <20250505223922.2682012-44-sashal@kernel.org>
Date: Mon,  5 May 2025 18:32:00 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Josh Poimboeuf <jpoimboe@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Sasha Levin <sashal@...nel.org>,
	peterz@...radead.org
Subject: [PATCH AUTOSEL 6.12 044/486] objtool: Properly disable uaccess validation

From: Josh Poimboeuf <jpoimboe@...nel.org>

[ Upstream commit e1a9dda74dbffbc3fa2069ff418a1876dc99fb14 ]

If opts.uaccess isn't set, the uaccess validation is disabled, but only
partially: it doesn't read the uaccess_safe_builtin list but still tries
to do the validation.  Disable it completely to prevent false warnings.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Link: https://lore.kernel.org/r/0e95581c1d2107fb5f59418edf2b26bba38b0cbb.1742852846.git.jpoimboe@kernel.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 tools/objtool/check.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d8aea31ee393a..175f8adb1b76d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3352,7 +3352,7 @@ static int handle_insn_ops(struct instruction *insn,
 		if (update_cfi_state(insn, next_insn, &state->cfi, op))
 			return 1;
 
-		if (!insn->alt_group)
+		if (!opts.uaccess || !insn->alt_group)
 			continue;
 
 		if (op->dest.type == OP_DEST_PUSHF) {
@@ -3819,6 +3819,9 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 			return 0;
 
 		case INSN_STAC:
+			if (!opts.uaccess)
+				break;
+
 			if (state.uaccess) {
 				WARN_INSN(insn, "recursive UACCESS enable");
 				return 1;
@@ -3828,6 +3831,9 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 			break;
 
 		case INSN_CLAC:
+			if (!opts.uaccess)
+				break;
+
 			if (!state.uaccess && func) {
 				WARN_INSN(insn, "redundant UACCESS disable");
 				return 1;
@@ -4303,7 +4309,8 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
 	if (!insn || insn->ignore || insn->visited)
 		return 0;
 
-	state->uaccess = sym->uaccess_safe;
+	if (opts.uaccess)
+		state->uaccess = sym->uaccess_safe;
 
 	ret = validate_branch(file, insn_func(insn), insn, *state);
 	if (ret)
-- 
2.39.5