From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8BCB14B0CA3; Tue, 15 Sep 2026 16:52:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789491124; cv=none; b=Ly4TLVMDSFYYs9yrDhU9KQ51aLTMddB1lKyWFlWEGQ5jh5W/HueSwA2hjw1pDUcjkhpx2Tbap0F8zsKB4PCjNLdnffVOQhkyGudF98iwieg1rOKrdEsUyNMkDadG5dyGHByQzB7yQGTGGp8vuaabsFVAub8cUwt0rNZR44OthdM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789491124; c=relaxed/simple; bh=/UR+2Iq7w8FYlaxEN7+1nLp8xgJdzaPnKXZV2EHPGQI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mY4EQ76IUyXMU79wM65+X9nnF6Pdmp+cqEE7KUugv6vDBDnToIU7Y+zH5f+2s5xfKLZDcmojObf6DZu7JXwDWktoTINZ1vWy/xhFiSWD3SfsiQ5ERy0CQc31iXChBXkZB6STM7h2BR4hXGpCHojvdhQH8tlDb86391W5Ei4sLs8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I2gPH+LF; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="I2gPH+LF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 050291F00893; Tue, 15 Sep 2026 16:52:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789491122; bh=AAegg1HqQc2zlyPsCFndE7BU31mvGmt6H10k5+2dIJY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=I2gPH+LFzLYZALBDt0ClbZdP2ilKcDCHRUfiBdPm3idQOsDqpB7q84aLX1rNrpsIi wqf4NIRZrAMGKEqi89jARH+zbeojQb+KDUw89DWC124dgGma0vkuOyh7VKF0jaex++ b57xMMAACGyAnBWTbpAotn+pMoUc4jo98m/cRL6VnMgiAuTr01RxuVn3RxfhUqUF2V HDTTUD4Q37fkbMXjP61re8NqNAxmKlEzdXEOYIYEP0ixfcH/BkcKa66oKfC9x6HBgf 1HGcQYQ/iY9/7C56XCgwfGL8/S8XFNbJezbtToRJkfqoCvtrHQsII7a2j185CneqPi WT5WUhI+hl6tw== Date: Tue, 15 Sep 2026 09:52:01 -0700 From: Kees Cook To: "Lorenzo Stoakes (ARM)" Cc: Linus Torvalds , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Masahiro Yamada , Alexey Gladkov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Arnd Bergmann , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Ilias Apalodimas , Josh Poimboeuf , Peter Zijlstra , Miguel Ojeda , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?iso-8859-1?Q?=D6zkan?= , Jonathan Corbet , Randy Dunlap , "Gustavo A. R. Silva" , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, Jens Axboe , linux-hardening@vger.kernel.org Subject: Re: [PATCH v2 20/21] kbuild: build rust crates in parallel with the rest of the build Message-ID: <202609150951.73C4F16EFB@keescook> References: <20260914-build-speedup-v2-0-39817ec5db23@kernel.org> <20260914-build-speedup-v2-20-39817ec5db23@kernel.org> <202609141133.7CA979C89@keescook> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Sep 15, 2026 at 12:58:10PM +0100, Lorenzo Stoakes (ARM) wrote: > Since this _still_ gives you a significant speed up on bigger boxes, I think > it's fine as-is. > > The LLM says a fix for this would need significant work - a cross-instance lock > and an on-demand rust/ build. So I think best as a follow-up? Sure! And I defer to the Rust folks on all of this. I just wanted to note the possibly unintended behavioral change there. Thanks for examining it! -- Kees Cook