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 BB5F0C7115B for ; Thu, 19 Jun 2025 08:42:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5DDC96B008A; Thu, 19 Jun 2025 04:42:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 58EAA6B008C; Thu, 19 Jun 2025 04:42:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4CB786B0092; Thu, 19 Jun 2025 04:42:18 -0400 (EDT) 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 3EB1B6B008A for ; Thu, 19 Jun 2025 04:42:18 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 1D4081D520B for ; Thu, 19 Jun 2025 08:42:18 +0000 (UTC) X-FDA: 83571508356.07.7E9ED74 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf27.hostedemail.com (Postfix) with ESMTP id 1B15240002 for ; Thu, 19 Jun 2025 08:42:15 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=none; spf=pass (imf27.hostedemail.com: domain of christophe.leroy@csgroup.eu designates 93.17.236.30 as permitted sender) smtp.mailfrom=christophe.leroy@csgroup.eu; dmarc=pass (policy=quarantine) header.from=csgroup.eu ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1750322536; 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:content-transfer-encoding:in-reply-to: references; bh=LTj8xM2TR/lqvoVvPHJizZTsyvGRlEncFQI6noYeYPg=; b=IOOxlqm+lc65ez6PF1QOH00gBHUFcjdgO2VknArttFHVF1xuRACPYscLmIPdBHpCwKStEg +0AEUz4sHwhoT9KM96POrNpiq8j62NCPVaXYa2CTPTOT+1cEGiiFQy/t5Te5GmCBRdREX9 YbFKLmglbV+6k1DU0VoOZdnYOEOr5vg= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750322536; a=rsa-sha256; cv=none; b=i78WFk9gUVHEyngQte0ALWt8oZnvK4Z3KazT/ar376WHpKUfZG2yNa8CIeCQuK2OIgZaeQ olLUlv1fxNjuhbgtkQnNgjN8RNn7ir7o2Yn8kvvH91G6rljORUROvsmVn6rYjQbjgnyjTa fik/DAG2MsURpQm7N3svOYKxPvrAL74= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=none; spf=pass (imf27.hostedemail.com: domain of christophe.leroy@csgroup.eu designates 93.17.236.30 as permitted sender) smtp.mailfrom=christophe.leroy@csgroup.eu; dmarc=pass (policy=quarantine) header.from=csgroup.eu Received: from localhost (mailhub3.si.c-s.fr [192.168.12.233]) by localhost (Postfix) with ESMTP id 4bNDck1kVXz9tSq; Thu, 19 Jun 2025 10:42:14 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8n3SkZ0cbxug; Thu, 19 Jun 2025 10:42:14 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4bNDck0sP1z9tHZ; Thu, 19 Jun 2025 10:42:14 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 183538B790; Thu, 19 Jun 2025 10:42:14 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id Y0gL91Rd_iyf; Thu, 19 Jun 2025 10:42:14 +0200 (CEST) Received: from [192.168.235.99] (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id CDFC18B78C; Thu, 19 Jun 2025 10:42:13 +0200 (CEST) Message-ID: <6f58923f-5ee2-41c6-bb73-8e0fb9ad9a96@csgroup.eu> Date: Thu, 19 Jun 2025 10:42:13 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: fr-FR To: Dave Hansen Cc: Linus Torvalds , Thomas Gleixner , Daniel Borkmann , "linux-mm@kvack.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" From: Christophe Leroy Subject: Redundant barrier_nospec() added by commit 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Stat-Signature: kr7qsxq49n8pq659htqzdc7db7yojyhh X-Rspam-User: X-Rspamd-Queue-Id: 1B15240002 X-HE-Tag: 1750322535-151768 X-HE-Meta: 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 fRZ2uMdo wRzVAbHFDwY/hM2qD7l8X2RsizgeAEvdfRvUzPX7I/IEsbc5uXVTaOBI3WfVrJxKEdQ1jMr1NpSoIRLIeJxmeHsAjfSJt+r6ol+dG9NdBP5I0N7VPleaHFUL+wFx8n+BDbR/qvrh52i17mQRU9sTOEkJbGsKFDtnXwwocCP2QpoOO6ZbRTPni4aHtv+rG42gXdU0GK4ht6yVGRBJtzTei9k3FRuCP7Exora2IrmG10gzgVpWjB1JVfYAVAXGwR7DNHdj5 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: Hello Dave, In commit 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") you add barrier_nospec() to copy_from_user(). There is already a barrier_nospec() in allow_read_from_user() which is called by raw_copy_from_user(), see commit 8524e2e76441 ("powerpc/uaccess: Perform barrier_nospec() in KUAP allowance helpers"). Why do you need an additional one ? And why only copy_from_user() and not also other places like copy_from_user_iter() for instance ? Thanks Christophe