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 378053161A3; Thu, 9 Jul 2026 16:23:48 +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=1783614229; cv=none; b=Vslo70LCHAMSKIy4hTivTv4gkU4x4EtL3lpznDOtPWzm/5Hh/ftw2bM80nyRKsX0DTgOAzmvS61K2ohQgeFWSRY7VEV0xKPWvf9eMzr5ui37ezhYF3ZEYRAMeE7DiksnufM5U3+MIoDbl1pdN/uOcXG4kx8co+JCNm/5798gAoo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783614229; c=relaxed/simple; bh=PYgbxg9gRqFkI+16o1eOO4t2hXv+bYRFkiZ971QQZko=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Tn34AiouGwwj9hPyUxs/zP5ShJmj/EMRfCsf7YAFxY9g+Cf1Sslrl29Bnj/Lxyj3wyzMlvcDLkuW5hO/SHvw6JqXRvHo6xLt8h12NsC4yX2r1B8JJGf7mH/QbS5NrJCaz5A9XoOHhmkW3WN1MRqOtv2dWuSPMCx029TkaJS6488= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dEsGFvG0; 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="dEsGFvG0" 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> 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: <20260707190253.768842729@kernel.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