From: Sasha Levin <sashal@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Wentao Zhang <wentaoz5@illinois.edu>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Bill Wendling <morbo@google.com>, Chuck Wolber <chuck@wolber.net>,
Dmitry Vyukov <dvyukov@google.com>,
Justin Stitt <justinstitt@google.com>,
kasan-dev@googlegroups.com, linux-kbuild@vger.kernel.org,
llvm@lists.linux.dev, Marco Elver <elver@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nicolas Schier <nsc@kernel.org>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>
Subject: Re: [RFC PATCH 16/20] coverage: add MC/DC measurement
Date: Wed, 28 Oct 2026 16:39:17 -0400 [thread overview]
Message-ID: <20261028203918.2355157-1-sashal@kernel.org> (raw)
In-Reply-To: <20261028191432.GA669102@ax162>
On Wed, Oct 28, 2026 at 12:14:32PM -0700, Nathan Chancellor wrote:
>On Wed, Oct 28, 2026 at 07:59:40AM -0400, Sasha Levin wrote:
>> Larger decisions, and decisions the compiler can't instrument, produce
>> warnings. Starting with Clang 22 they are kept from becoming errors
>> with CONFIG_WERROR; older versions can't be used together with it.
>
>What is the reason for keeping these warnings in the build as opposed to
>just disabling them altogether? Are developers expected to address them
>and if so, how? It seems odd to keep them in the build but prevent them
>from breaking the build unless they are not intended to be acted on, in
>which case they should just be disabled outright.
They're not meant to be acted on. Clang only put them in a warning group
(-Wpgo-coverage) in 22, so before that there was no way to turn them
off, which is why I just left them on. I'll disable them in v2 where
Clang allows it.
--
Thanks,
Sasha
next prev parent reply other threads:[~2026-10-28 20:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-28 11:59 [RFC PATCH 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 01/20] coverage: move gcov and kcov under kernel/coverage/ Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 02/20] kbuild: unify static coverage instrumentation as COVERAGE_PROFILE Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 04/20] compiler_types.h: Don't instrument __always_inline functions for coverage Sasha Levin
2026-10-28 13:51 ` Peter Zijlstra
2026-10-28 14:01 ` Peter Zijlstra
2026-10-28 16:45 ` Sasha Levin
2026-10-29 5:49 ` Chuck Wolber
2026-10-28 11:59 ` [RFC PATCH 07/20] perf: Always inline the empty perf_lopwr_cb() stub Sasha Levin
2026-10-29 12:01 ` sashiko-bot
2026-10-28 11:59 ` [RFC PATCH 10/20] x86/sev: Use non-instrumented bitops in the GHCB accessors Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 11/20] objtool: Detect code coverage instrumentation in noinstr code Sasha Levin
2026-10-28 14:11 ` Peter Zijlstra
2026-10-28 16:45 ` Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 12/20] x86/sev: Stop excluding noinstr.o from code coverage Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 14/20] coverage: add Clang's source-based " Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 15/20] x86: Enable " Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 16/20] coverage: add MC/DC measurement Sasha Levin
2026-10-28 19:14 ` Nathan Chancellor
2026-10-28 20:39 ` Sasha Levin [this message]
2026-10-28 11:59 ` [RFC PATCH 18/20] kconfig: add CC_HAS_CONDITION_COVERAGE for MC/DC support detection Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 19/20] gcov: add MC/DC condition coverage support Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 20/20] Documentation: dev-tools: document the common code coverage interface Sasha Levin
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