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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E905DC4332F for ; Tue, 12 Dec 2023 20:26:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 756536B0364; Tue, 12 Dec 2023 15:26:33 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6E0986B0365; Tue, 12 Dec 2023 15:26:33 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 558996B0366; Tue, 12 Dec 2023 15:26:33 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 42B3A6B0364 for ; Tue, 12 Dec 2023 15:26:33 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 173E2A202B for ; Tue, 12 Dec 2023 20:26:33 +0000 (UTC) X-FDA: 81559299066.01.5401BA9 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by imf21.hostedemail.com (Postfix) with ESMTP id AE2BC1C0009 for ; Tue, 12 Dec 2023 20:26:30 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="QK3xwh7/"; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf21.hostedemail.com: domain of broonie@kernel.org designates 145.40.73.55 as permitted sender) smtp.mailfrom=broonie@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1702412791; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ITS9iepxKmDBteakc9JcBmcwe4qkWaGAUfkgjLJxKz8=; b=OX0S/Qu4TtSXQkvJYjbWNFGdUFRsNthZfI3PSPfEmKoEjaf27pLEHcgw1tAa0aETcQ97x0 LHh5gKp/J6e+4RLSk+au3AhZ7NY04/Wmlyozcn5inzRyNSGKV1vnqC26j34W5nMfKomSu3 ocplcX4PqSDXe0I/kU/haNDE6hBiLr8= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="QK3xwh7/"; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf21.hostedemail.com: domain of broonie@kernel.org designates 145.40.73.55 as permitted sender) smtp.mailfrom=broonie@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1702412791; a=rsa-sha256; cv=none; b=jkZmMFwMzSQ2dwyDvFg0enIYZSiTsIdtwA/EsR0RrSx6F0xZjnZ/UD2fM95JW+CBGt8/AT Wl84wo2mlJjRKUxHnwDKxq7Bzd95lT9s4MLHjUT5ZekJ4vaMd4lyX3up8utPWOt28A2p48 D6vmh7ZOCL8XkqvssFiYTllt5R8440A= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 444C0CE1997; Tue, 12 Dec 2023 20:26:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C190EC433C7; Tue, 12 Dec 2023 20:26:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702412785; bh=ITS9iepxKmDBteakc9JcBmcwe4qkWaGAUfkgjLJxKz8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QK3xwh7/RovgLawsgEE27tFvsEmWXv9zo7z8pvLyL07K+1LB60nrenIjCvuljOe6O 41c/d6u9DpvjRjFbkGD3P7jmXStQB53cqmZKdEcnFfWLpGUOCj6vXd8lnyrF285YBk lVETctoAeX57YmnxNLRbavEXKvRsDBaDhwBiBYye6h5MN+tCnF67DNpZdysaYny5kM t6INZGptEmFHhK3ZOTufikrTYp0MGbYMADqUFNtympWn8LwrjrDYUNKzFAW2JmdTUH jSwlGihfJo7Y1K458B8sp76wN0x2qFUaS7cUbWtzteUthuknj5NGIFYj3sBiBRZ0Ms PcHfkNUJGI2Qg== Date: Tue, 12 Dec 2023 20:26:15 +0000 From: Mark Brown To: "Edgecombe, Rick P" Cc: "corbet@lwn.net" , "ardb@kernel.org" , "maz@kernel.org" , "shuah@kernel.org" , "Szabolcs.Nagy@arm.com" , "keescook@chromium.org" , "james.morse@arm.com" , "debug@rivosinc.com" , "akpm@linux-foundation.org" , "catalin.marinas@arm.com" , "oleg@redhat.com" , "arnd@arndb.de" , "ebiederm@xmission.com" , "will@kernel.org" , "suzuki.poulose@arm.com" , "oliver.upton@linux.dev" , "brauner@kernel.org" , "fweimer@redhat.com" , "aou@eecs.berkeley.edu" , "linux-kernel@vger.kernel.org" , "paul.walmsley@sifive.com" , "hjl.tools@gmail.com" , "linux-mm@kvack.org" , "palmer@dabbelt.com" , "kvmarm@lists.linux.dev" , "linux-arch@vger.kernel.org" , "thiago.bauermann@linaro.org" , "linux-doc@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kselftest@vger.kernel.org" , "linux-riscv@lists.infradead.org" Subject: Re: [PATCH v7 02/39] prctl: arch-agnostic prctl for shadow stack Message-ID: <28c584ff-ef25-464f-852c-c5ddf66e5906@sirena.org.uk> References: <20231122-arm64-gcs-v7-0-201c483bd775@kernel.org> <20231122-arm64-gcs-v7-2-201c483bd775@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="LPMEijolhyLOy67U" Content-Disposition: inline In-Reply-To: X-Cookie: If rash develops, discontinue use. X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: AE2BC1C0009 X-Stat-Signature: 39ejkpspnro5uz5fm1j31rkkyxqmchx7 X-Rspam-User: X-HE-Tag: 1702412790-435823 X-HE-Meta: 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 +q0ncYsr AYfsOcsCEHRV8RuLDh2uSf9/YIG7xhlGmMPqKZaepRkC4ZnoRJi+pr1mmF+/pgKOseKnKAGKnTRE0t5VmWJJNHAXVNLCjIGehfDjxTdfbSW5W2aBxy5zStp8SRArBLdy6dQvKXVPKClrbAlQmCdLV1Yk1vrJ7EBkPaYXxiBLQCrZNmgAvwnOXim0RyixLYVr+9WS07CitBLxMAkxqEFnjMLsvETZhQ+OuHoFU6pvgfUoZwTCl2Lom8+9keRBMoiRWgLdvuqQUfU4tTVNqxi5w2tR/wKUzqgqaX8NYuT/yPx6xCp6qgpXRKaz3z2Y8wbz1xSg8NQYRc9l7bsy0xt4qR6MekpAE6/LTVGHFRmysdPjYwlu5EA16eZxYgwsYmAmHda/9 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --LPMEijolhyLOy67U Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Dec 12, 2023 at 08:17:09PM +0000, Edgecombe, Rick P wrote: > On Wed, 2023-11-22 at 09:42 +0000, Mark Brown wrote: > > These features are expected to be inherited by new threads and > > cleared > > on exec(), unknown features should be rejected for enable but > > accepted > > for locking (in order to allow for future proofing). > The reason why I stuck with arch_prctl when this came up is that CRIU > (and probably other ptracers) needs a way to unlock via ptrace. ptrace > arch_prctl() can do this. Did you have a plan for unlocking via ptrace? The set of locked features is read/write via ptrace in my arm64 series, that's architecture specific unfortunately but that seems to be the way with ptrace. In general if things have a need to get at prctl()s via ptrace we should just fix that, at least for arm64 there's things like the vector lengths that are currently controlled via prctl(), but it shouldn't be a blocker for the locking specifically. --LPMEijolhyLOy67U Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmV4weYACgkQJNaLcl1U h9BRvwf/S9so8PzoqYCQJHpoRcvkwkq4+soyG3JSVYBAX+IsKPFGhH92O4Zp5DZJ aASTrqwmW/PsW8TX8LOC1w1a2OadrpSIa4r8kxsWZWdzkg6OHWcZ/XlhGe4a1yMF kUw36Z5PIqQRf02YHLYdelHq6/xswjma9YcOb5iVB0TZAL5mQw/2CHXr4ahGlAFr Pj4wVYIkXRohUP6gR04RuD61bfD4WIFneYjIjzPYYYo9yxWSiiOrpO/MD1Jb7bQe BaUHpGEsUZysAGRWxVvg+6v85VbHn/PYX8xT5xk9AmfYP8KM8HaClCKtzVBg//10 a9fZcXajnHu4O2S5h6Jsn5IYnbwpcg== =ln+K -----END PGP SIGNATURE----- --LPMEijolhyLOy67U--