From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DBE1CC44506 for ; Thu, 9 Jul 2026 16:23:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=PVNPrFU1PGB9ZkQlUfz3ePnrtlBWmUW1vci7gbMc020=; b=0z+k6ZLwuStxoB2hdSCHG12i74 +g1Q28j1JboxUq3I7xEV8WpNENJZjoDIKPhxqecP4oq07AIJQgIL/x3DDSKPjD+DBbaKCzb/aIlnX R7c3QsOjl8zY46qM9Wb4Pn4ZmV71vJDgjQWHfCi0y4XtZXYYS1KYuqL8IzWlUijf9sfvTPRKRQZUR aLRv2g31AZn8VU6ED9UfqMsRNDCGk7Cc2VwzmbPsaew3NNgC8wmXLU5IT8pGTV97rXMNSm75SQ5eF icmtBVtmgUhQPlQyXaenq4JxWXILLzQwj/Qljuo13DqbOO66RaL+hoHSaWNacqkHrZ29gyqYo9krw 1oGoPYlw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1whrXT-0000000321R-1UOm; Thu, 09 Jul 2026 16:23:51 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1whrXQ-000000031zu-3R3W; Thu, 09 Jul 2026 16:23:48 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 16346405C4; Thu, 9 Jul 2026 16:23:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3F271F00A3A; Thu, 9 Jul 2026 16:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783614228; bh=PVNPrFU1PGB9ZkQlUfz3ePnrtlBWmUW1vci7gbMc020=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=dEsGFvG0entc+CRLpmVOaUBCJG4D03DxA7ZPHMA+0bz+ArzFZ4oZ25h3XsZAVyxRR x10/LoE7lElTzHD06XWpE2m6rYMtKRUGebUhQapIBfB+ep4fG37Ng0RaVsx6GdmjM4 W83GkVnhwTOjct2PRlsvXAgfF8WsuxadhgjUrZKIFxbiAgM07wgLkRHLtXBID76WXL vXpw2i5GZ2AEQYDFtIGxLdWwAY7AsLhILvFuoodFrluXUPHF4msNedMhyKYrHXoB8T JJj34DTu2/8Sq2sDLaSW1Xi2u/2ZNgMk1vZ51THvkxDDB/2K6ZsmwZ7UkwuT1KfO4D Hq6xN5eyBwNEw== Date: Thu, 9 Jul 2026 09:23:47 -0700 From: Kees Cook To: Thomas Gleixner Cc: LKML , Peter Zijlstra , Michael Ellerman , Shrikanth Hegde , linuxppc-dev@lists.ozlabs.org, Huacai Chen , loongarch@lists.linux.dev, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Sven Schnelle , linux-s390@vger.kernel.org, x86@kernel.org, Mark Rutland , Jinjie Ruan , Andy Lutomirski , Oleg Nesterov , Richard Henderson , Russell King , Catalin Marinas , Guo Ren , Geert Uytterhoeven , Thomas Bogendoerfer , Helge Deller , Yoshinori Sato , Richard Weinberger , Chris Zankel , linux-arm-kernel@lists.infradead.org, linux-alpha@vger.kernel.org, linux-csky@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-um@lists.infradead.org, Arnd Bergmann , Vineet Gupta , Will Deacon , Brian Cain , Michal Simek , Dinh Nguyen , "David S. Miller" , Andreas Larsson , linux-snps-arc@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, Michal =?iso-8859-1?Q?Such=E1nek?= , Jonathan Corbet , linux-doc@vger.kernel.org Subject: Re: [patch 02/18] randomize_kstack: Provide add_random_kstack_offset_irqsoff() Message-ID: <202607090922.4ECAE32C07@keescook> References: <20260707181957.433213175@kernel.org> <20260707190253.768842729@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260707190253.768842729@kernel.org> X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Tue, Jul 07, 2026 at 09:06:02PM +0200, Thomas Gleixner wrote: > add_random_kstack_offset() uses get/put_cpu_var() which is pointless > overhead when it is invoked from low level entry code with interrupts > disabled. > > Provide a irqsoff() variant, which avoids that. > > Signed-off-by: Thomas Gleixner Seems good. I don't think macro'izing the interior is worth it since both cases are very short, with only the lockdep and raw bits changed. Reviewed-by: Kees Cook -Kees -- Kees Cook