From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B6B1C7C for ; Sat, 29 Jul 2023 09:10:18 +0000 (UTC) Received: from mail-4316.protonmail.ch (mail-4316.protonmail.ch [185.70.43.16]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBC9C46B3 for ; Sat, 29 Jul 2023 02:10:03 -0700 (PDT) Date: Sat, 29 Jul 2023 09:09:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1690621802; x=1690881002; bh=rixSAlF8H68fR6m3THBV7cCNL7So1w86OXDiq2xYBjU=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=fnB7DKQrA5Mk3rcM0qdH1bUwWWwZruoJbh//pq9ObBMiIuInGNNV8FSd6v4xXHd6Z eBJ8TiauGbt8+31hQ3QoQ4JHTlkaaW9jl4S7EYP6FyrdW2wF6YFPFlEN2cUxt82UP3 5qF43KJejvkdGm5PTJ/fF3eQsjH4LrYxXW3FYBTe9isFjDp/E3SuvmKGEPbIUkocf0 Q+Haw7xBMFQ8sy0zpMg+NIiVNOO+2IJ1plEaaZtZB8OEGBH+r+OdwO7EoV8EhsexrD UPZ7X097/SV6kA4GbIurWboVWrBdHSy36+FRBLCVOV/XPPOhsdeNGcyaSOCqnyQUGf RAEFQxJXWLkyg== To: Miguel Ojeda , Wedson Almeida Filho , Alex Gaynor From: Benno Lossin Cc: Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Andreas Hindborg , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Rodriguez Reboredo Subject: [PATCH v3 06/13] rust: init: make initializer values inaccessible after initializing Message-ID: <20230729090838.225225-7-benno.lossin@proton.me> In-Reply-To: <20230729090838.225225-1-benno.lossin@proton.me> References: <20230729090838.225225-1-benno.lossin@proton.me> Feedback-ID: 71780778:user:proton Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Previously the init macros would create a local variable with the name and hygiene of the field that is being initialized to store the value of the field. This would override any user defined variables. For example: ``` struct Foo { a: usize, b: usize, } let a =3D 10; let foo =3D init!(Foo{ a: a + 1, // This creates a local variable named `a`. b: a, // This refers to that variable! }); let foo =3D Box::init!(foo)?; assert_eq!(foo.a, 11); assert_eq!(foo.b, 11); ``` This patch changes this behavior, so the above code would panic at the last assertion, since `b` would have value 10. Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Alice Ryhl Signed-off-by: Benno Lossin --- v2 -> v3: - added Reviewed-by's from Martin and Alice. rust/kernel/init/macros.rs | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/rust/kernel/init/macros.rs b/rust/kernel/init/macros.rs index 2bad086cda0a..cfeacc4b3f7d 100644 --- a/rust/kernel/init/macros.rs +++ b/rust/kernel/init/macros.rs @@ -1075,13 +1075,13 @@ macro_rules! __init_internal { // In-place initialization syntax. @munch_fields($field:ident <- $val:expr, $($rest:tt)*), ) =3D> { - let $field =3D $val; + let init =3D $val; // Call the initializer. // // SAFETY: `slot` is valid, because we are inside of an initialize= r closure, we // return when an error/panic occurs. // We also use the `data` to require the correct trait (`Init` or = `PinInit`) for `$field`. - unsafe { $data.$field(::core::ptr::addr_of_mut!((*$slot).$field), = $field)? }; + unsafe { $data.$field(::core::ptr::addr_of_mut!((*$slot).$field), = init)? }; // Create the drop guard: // // We rely on macro hygiene to make it impossible for users to acc= ess this local variable. @@ -1107,12 +1107,12 @@ macro_rules! __init_internal { // In-place initialization syntax. @munch_fields($field:ident <- $val:expr, $($rest:tt)*), ) =3D> { - let $field =3D $val; + let init =3D $val; // Call the initializer. // // SAFETY: `slot` is valid, because we are inside of an initialize= r closure, we // return when an error/panic occurs. - unsafe { $crate::init::Init::__init($field, ::core::ptr::addr_of_m= ut!((*$slot).$field))? }; + unsafe { $crate::init::Init::__init(init, ::core::ptr::addr_of_mut= !((*$slot).$field))? }; // Create the drop guard: // // We rely on macro hygiene to make it impossible for users to acc= ess this local variable. @@ -1138,11 +1138,13 @@ macro_rules! __init_internal { // Init by-value. @munch_fields($field:ident $(: $val:expr)?, $($rest:tt)*), ) =3D> { - $(let $field =3D $val;)? - // Initialize the field. - // - // SAFETY: The memory at `slot` is uninitialized. - unsafe { ::core::ptr::write(::core::ptr::addr_of_mut!((*$slot).$fi= eld), $field) }; + { + $(let $field =3D $val;)? + // Initialize the field. + // + // SAFETY: The memory at `slot` is uninitialized. + unsafe { ::core::ptr::write(::core::ptr::addr_of_mut!((*$slot)= .$field), $field) }; + } // Create the drop guard: // // We rely on macro hygiene to make it impossible for users to acc= ess this local variable. --=20 2.41.0