From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.197 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793140759; b=IyqKCrmXKGIalxi/9TvQSqgjWuqO/iTJBGiYg1uQ6oAiipDW+fbO59ID28WI6enxiuiG GRxCV0IkSNBf71l4d61oVSOXabCuObiUDCDuZz0ln5UYAAZLBeRTJEjdgQwucNrvqxVvT o2liwdlMyUCvZjcL5TQsMAhOdiA9E5OI9O+1Hmz5f/t+6SYgGbjKXuC62MNbHmPs0oR12 U/vuAFLJlj8rzwQF9aHujppje7jMSdH8JALI7ITj4dhKeWIzoiM31g9EvAgOGfxrlIQJ+ VWHlmPGQ0n1KvIAKcwWMo7NjndvODhRkIw04S5stHXrj9Du6M5qn8JT+yfvvfR4Q33A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793140759; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Received:Date:In-Reply-To: Mime-Version:References:X-Mailer:Message-ID:Subject:From:To:Cc: Content-Type; bh=dWBu3E1+9O630leKOxiPf33Qem+izCRkowC6gFS9sVM=; b=EEAwN0SKYkKN9PvBbzjAHIbUiWW+IekWQUK+KkKwZjiCsJ9Ef+4CZKABDe5pqa7qJgOZ BtACV2kYFygMD9Ww8SLU00m2Vkb11cD1vPzUo793ES6Z5OVkWvku8EBo5IXLvfGtRoZam BxUAT0nCwwCL1x34FKbIZ07yxDAJbugrwLpmkp3BaHHGQjqtWUGd1jG1uPBUKsdDToFJp AQDp+aXFbaMtyIavSBr+zo60o9ORWqY3X0TA4Dub/knyAcYTHYMISeVhN6PDjXZ7N6XeG hORejGdvAcJrqY9QsXyXTssdWqGegv7UAWkahtjoR4bvQjevUNq5P2rzMq2vnlSfuhA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=Ecx7Z7Yr; arc=none smtp.remote-ip=74.125.82.197 Received: from mail-dy1-f197.google.com (mail-dy1-f197.google.com [74.125.82.197]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C1A9606A331 for ; Tue, 27 Oct 2026 22:39:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5C1A9606A331 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=Ecx7Z7Yr Received: by mail-dy1-f197.google.com with SMTP id 5a478bee46e88-30bcb065bfdso523840eec.0 for ; Tue, 27 Oct 2026 15:39:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20260707; t=1793140753; x=1793745553; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=dWBu3E1+9O630leKOxiPf33Qem+izCRkowC6gFS9sVM=; b=Ecx7Z7YrTfUji8sYJyAUwmTYp73g8n8XJtV3g1Ovi0aAYrvFnBJ3+xg5yXNOklXPYQ z9C3C95INgU3Kxi4Dixa8qWSZcVtAka2S3TI5rED3YKw4tSh6V0biyKwhustYNH9cnlE s18xrBbLvfRBcBfijZUAZvaSiYrJlHLwXZtz+yS9CFjvDRQUUw0KuHx6xfU6zY5z9iNs 1euMv0gAIOGjLHzqjjULrUrhmVPTbifnO2Nd/4PNGMj5bXIEi4HnL9xBa4Lag60EMfqh lX38QYyHu9liDYA6R11F3C/KlzQcB7IhBtPte3IL0MvSanWi+JKnktIib9zaD54mxDob VOzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793140753; x=1793745553; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=dWBu3E1+9O630leKOxiPf33Qem+izCRkowC6gFS9sVM=; b=UlzWfbwGcErBGwwtWluS54qQMwnf0ihDdvitPKpOdQVeCgeEgPyiA74xqlYYoEFAmz xUWhu76ylX/R9aMAbatp/fXRnrFw6hErBDnHMk43L1qPeYLlYq9hSDBPKTB++Jwr54x5 AtZ5uQs53vPN6y5d92Sr+MznLAGZwfdqlFMqpy8y3t6G6e+iL4a1if5cMCL8EY4q1kZm BEhoEHG2PZO2Vdqu8p6SM23HVPb1UZTp6HNTxNLBvXeldU+Z2OqdhRNr0txM9zKMcJbh UL4Ok69yo576VSLWRxdCWyvu3C+4AQmgZaTdlHQNVwFrpSXGp98hs2ekWRX8dHEovqYC SOiw== X-Forwarded-Encrypted: i=1; AKwUvBwvgj0v3aay0sxDmsuQwI2rNAekW6L3GuqY1ySk6gV6uACSOtVkM9VGgvzah1z/49mvnd9jLNQ6+w==@vger.kernel.org X-Gm-Message-State: AFq9FYIfs4dHokI2+IzWOLgLm/Z1TbR9KMlfDUMeNKLbCWg/7Pcspk72 Ghk6nT75bH17jfDYK2BZWOfDVlMQDBL415IgOHcRZdAwvFDiE7NPRRzs24rM3JFlNYLnymavx2w V3bzHf0O/4Q== X-Received: from dybnl11.prod.google.com ([2002:a05:7300:cf8b:b0:36a:117:523b]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:693c:250d:b0:369:f5f6:36a7 with SMTP id 5a478bee46e88-36a2014b887mr1132027eec.16.1793140751881; Tue, 27 Oct 2026 15:39:11 -0700 (PDT) Date: Tue, 27 Oct 2026 15:38:36 -0700 In-Reply-To: <20261027223847.652884-1-irogers@google.com> X-Mailing-List: linux-sh@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 References: <20261027223847.652884-1-irogers@google.com> X-Mailer: git-send-email 2.56.0.313.g2479322e68-goog Message-ID: <20261027223847.652884-2-irogers@google.com> Subject: [PATCH v2 1/9] Compiler Attributes: Add __must_init macro From: Ian Rogers To: Kees Cook , Greg Kroah-Hartman , Miguel Ojeda , "Rafael J . Wysocki" , Danilo Krummrich Cc: Nathan Chancellor , Nick Desaulniers , Miguel Ojeda , "=?UTF-8?q?Christian=20K=C3=B6nig?=" , Zhihao Cheng , Zhongqiu Han , Sumanth Korikkar , Bill Wendling , Justin Stitt , driver-core@lists.linux.dev, llvm@lists.linux.dev, linux-hardening@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, linux-s390@vger.kernel.org, gfs2@lists.linux.dev, xen-devel@lists.xenproject.org, linux-mtd@lists.infradead.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Ian Rogers , Jonathan Corbet , Shuah Khan , Randy Dunlap , Andy Whitcroft , Joe Perches Content-Type: text/plain; charset="UTF-8" Clang supports the 'require_explicit_initialization' attribute on struct fields to indicate that a field must be initialized explicitly by the user when the object is constructed. When an aggregate initializer or uninitialized variable omits an annotated field, Clang emits a -Wuninitialized-explicit-init warning (enabled by default). Add the __must_init macro to include/linux/compiler_attributes.h (which is included by include/linux/compiler_types.h and include/linux/compiler.h) so kernel structs with error-prone initialization (such as mandatory callbacks or cleanup handlers) can enforce explicit initialization at compile time, as discussed at the Linux Plumbers Conference. The shorter __must_init spelling, rather than the attribute's full name, keeps annotated struct members readable and was suggested by Greg Kroah-Hartman. Note that Clang does not yet diagnose file-scope objects declared without any initializer (initializers at file scope that omit the field are diagnosed), see https://github.com/llvm/llvm-project/issues/232483. Also teach Sphinx (Documentation/conf.py), kernel-doc (tools/lib/python/kdoc/xforms_lists.py), and checkpatch.pl about the new attribute macro. Link: https://lpc.events/event/20/contributions/2392/ Link: https://lore.kernel.org/lkml/2026101532-fantastic-deafness-e04c@gregkh/ Acked-by: Miguel Ojeda Reviewed-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Acked-by: Greg Kroah-Hartman Signed-off-by: Ian Rogers --- Documentation/conf.py | 1 + include/linux/compiler_attributes.h | 12 ++++++++++++ scripts/checkpatch.pl | 1 + tools/lib/python/kdoc/xforms_lists.py | 1 + 4 files changed, 15 insertions(+) diff --git a/Documentation/conf.py b/Documentation/conf.py index 5ab26ce89daf..baaa4035258c 100644 --- a/Documentation/conf.py +++ b/Documentation/conf.py @@ -203,6 +203,7 @@ c_id_attributes = [ "__noreturn", "__packed", "__pure", + "__must_init", "__section", "__always_unused", "__maybe_unused", diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index 476c4c560d17..b9c0b56dd22e 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -322,6 +322,18 @@ */ #define __pure __attribute__((__pure__)) +/* + * Optional: not supported by gcc + * Optional: only supported since clang >= 20.0 + * + * clang: https://clang.llvm.org/docs/AttributeReference.html#require-explicit-initialization + */ +#if __has_attribute(__require_explicit_initialization__) +# define __must_init __attribute__((__require_explicit_initialization__)) +#else +# define __must_init +#endif + /* * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index c9840f5219c2..5232f66d2b80 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6860,6 +6860,7 @@ sub process { "noreturn" => "__noreturn", "packed" => "__packed", "pure" => "__pure", + "require_explicit_initialization" => "__must_init", "section" => "__section", "used" => "__used", "weak" => "__weak" diff --git a/tools/lib/python/kdoc/xforms_lists.py b/tools/lib/python/kdoc/xforms_lists.py index 320f977c5bac..3c744cbd2f34 100644 --- a/tools/lib/python/kdoc/xforms_lists.py +++ b/tools/lib/python/kdoc/xforms_lists.py @@ -36,6 +36,7 @@ class CTransforms: (CMatch("CRYPTO_MINALIGN_ATTR"), ""), (CMatch("__private"), ""), (CMatch("__rcu"), ""), + (CMatch("__must_init"), ""), (CMatch("____cacheline_aligned_in_smp"), ""), (CMatch("____cacheline_aligned"), ""), (CMatch("__cacheline_group_(?:begin|end)"), ""), -- 2.56.0.313.g2479322e68-goog