At present objtool only prints to the terminal when observing "fatal
warnings". This option lets you have it produce an error instead.

My use case for this is noinstr validation; so far I've never seen any
false warnings here, but it quite often detects real bugs. I'd like my
build to fail when I have those bugs.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 tools/objtool/builtin-check.c           | 6 ++++++
 tools/objtool/check.c                   | 7 ++-----
 tools/objtool/include/objtool/builtin.h | 1 +
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 387d56a7f5fb8da8435d0a3f5c05eeee66932c9b..dd70cbb98929b7f558c27766bda46ad276c0750d 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -94,6 +94,12 @@ static const struct option check_options[] = {
 	OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
 	OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
 	OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
+	/*
+	 *  For now, don't fail the kernel build on fatal warnings by default.
+	 *  These errors are still fairly common due to the growing matrix of
+	 *  supported toolchains and their recent pace of change.
+	 */
+	OPT_BOOLEAN(0, "fail-on-warn", &opts.fail_on_warn, "fail on fatal warnings"),
 
 	OPT_END(),
 };
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4ce176ad411fb12a10101bbedbb6180275941b4b..266896b46e92c5c4a3244aa73deb3a355e6d8f8d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4941,10 +4941,7 @@ int check(struct objtool_file *file)
 	}
 
 out:
-	/*
-	 *  For now, don't fail the kernel build on fatal warnings.  These
-	 *  errors are still fairly common due to the growing matrix of
-	 *  supported toolchains and their recent pace of change.
-	 */
+	if (opts.fail_on_warn && warnings)
+		return 1;
 	return 0;
 }
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index fcca6662c8b4b5e0048e54fada8694cc2e6ebc34..f9af81ad9f600044280085cd1a743609ce054a21 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -38,6 +38,7 @@ struct opts {
 	bool sec_address;
 	bool stats;
 	bool verbose;
+	bool fail_on_warn;
 };
 
 extern struct opts opts;

-- 
2.47.1.613.gc27f4b7a9f-goog

On Fri, Dec 13, 2024 at 11:31:30AM +0000, Brendan Jackman wrote:
> At present objtool only prints to the terminal when observing "fatal
> warnings". This option lets you have it produce an error instead.
> 
> My use case for this is noinstr validation; so far I've never seen any
> false warnings here, but it quite often detects real bugs. I'd like my
> build to fail when I have those bugs.
> 
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
>  tools/objtool/builtin-check.c           | 6 ++++++
>  tools/objtool/check.c                   | 7 ++-----
>  tools/objtool/include/objtool/builtin.h | 1 +
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
> index 387d56a7f5fb8da8435d0a3f5c05eeee66932c9b..dd70cbb98929b7f558c27766bda46ad276c0750d 100644
> --- a/tools/objtool/builtin-check.c
> +++ b/tools/objtool/builtin-check.c
> @@ -94,6 +94,12 @@ static const struct option check_options[] = {
>  	OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
>  	OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
>  	OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
> +	/*
> +	 *  For now, don't fail the kernel build on fatal warnings by default.
> +	 *  These errors are still fairly common due to the growing matrix of
> +	 *  supported toolchains and their recent pace of change.
> +	 */
> +	OPT_BOOLEAN(0, "fail-on-warn", &opts.fail_on_warn, "fail on fatal warnings"),

How about "--Werror" to mirror the compiler -Werror option.

-- 
Josh

On Sat, 14 Dec 2024 at 01:36, Josh Poimboeuf <jpoimboe@kernel.org> wrote:
> How about "--Werror" to mirror the compiler -Werror option.

Sure, --Werror sounds good to me.