From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6C589218823; Thu, 27 Feb 2025 21:32:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740691959; cv=none; b=flARFKv/pDk0WBi6iUlsIIZ2y3RSeBjI0/QDPXdU+55WqCL6GeFVPlxbXtMhVHMT+2N5X1SspNvejYcItTWuWZeffvNdmHIxZaLPW1Xa9+SC2KDZLoNPllbbMp6eEI0mXgPkc2y+shhXakQy6Rf6JRdsoaxUJQhnOWKg2rNMsIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740691959; c=relaxed/simple; bh=E3atdKrHAqEQcNejYjymMr9w/+VUCvBazKROwVdpSPI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jTZSOGedDvQvz7pE3EkosHFn/m02k2+weRlrpOEsHLtgCcnarDiCG1e0njm0U+0c3XiIfVXOQT6QqBzePc0fx3qlayVb9Z44lpHHmoigYJbLbrcYm0nS9Z4jw9VP4eC9aGQ/yl/bqHEccTIeiVZ0ernOegrSMSGuOQ+dVS94Dt8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA2C2C4CEDD; Thu, 27 Feb 2025 21:32:36 +0000 (UTC) Date: Thu, 27 Feb 2025 16:33:19 -0500 From: Steven Rostedt To: David Laight Cc: Linus Torvalds , Martin Uecker , Ralf Jung , "Paul E. McKenney" , Alice Ryhl , Ventura Jack , Kent Overstreet , Gary Guo , airlied@gmail.com, boqun.feng@gmail.com, ej@inai.de, gregkh@linuxfoundation.org, hch@infradead.org, hpa@zytor.com, ksummit@lists.linux.dev, linux-kernel@vger.kernel.org, miguel.ojeda.sandonis@gmail.com, rust-for-linux@vger.kernel.org Subject: Re: C aggregate passing (Rust kernel policy) Message-ID: <20250227163319.5b19a68a@gandalf.local.home> In-Reply-To: <20250227204722.653ce86b@pumpkin> References: <5d7363b0-785c-4101-8047-27cb7afb0364@ralfj.de> <20250226162655.65ba4b51@gandalf.local.home> <20250226165619.64998576@gandalf.local.home> <20250226171321.714f3b75@gandalf.local.home> <20250226173534.44b42190@gandalf.local.home> <20250227204722.653ce86b@pumpkin> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 27 Feb 2025 20:47:22 +0000 David Laight wrote: > Except that (IIRC) it is actually valid for the compiler to write something > entirely unrelated to a memory location before writing the expected value. > (eg use it instead of stack for a register spill+reload.) > Not gcc doesn't do that - but the standard lets it do it. I call that a bug in the specification ;-) -- Steve