From nobody Wed Dec 17 09:19:59 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E4B8331C584; Thu, 6 Nov 2025 11:50:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429827; cv=none; b=AaZCy6QILGeT+sGNfxITOk5M2o3XKCUEzSoC8fyYCfOiBNqNw5y7up2bTL7tK9w8yrUK9rmXkpTq2FL+0BQFNxjZENzhfy7+wMG5JljFVOt9xYK7M3eKGA4M6mLN/ZZqWMjIM5+eZ3ouo6mSmrYhu7NBSdumTit/roiD8BLBgdM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429827; c=relaxed/simple; bh=CInTZPEi9ILbXu4UpfN2lm4dHyQfqcOZ4rC45zzBAr0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dlONuJfgefjCU1UvQkXPoVcwbe3bz1sonqP0sdtxN/buLJ6UwHFSgqHKzic/KK6HbqFrVsrxT9NM92CVYD0IrfxxQcxARjIMKrec+p1SDNv/3wENCErPFdyW6Yibri6btap82vfa4sD0h/wgV3MkFpC9VUY4QNIfvCaXgzN06cc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmF1dFkz9sS8; Thu, 6 Nov 2025 12:32:13 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 343GnQeFijfY; Thu, 6 Nov 2025 12:32:13 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmF0qPPz9sRy; Thu, 6 Nov 2025 12:32:13 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 03FE98B773; Thu, 6 Nov 2025 12:32:13 +0100 (CET) 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 5UWr0kMelD5U; Thu, 6 Nov 2025 12:32:12 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 3723C8B77B; Thu, 6 Nov 2025 12:32:12 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 01/10] iter: Avoid barrier_nospec() in copy_from_user_iter() Date: Thu, 6 Nov 2025 12:31:19 +0100 Message-ID: <1c3b7384c5231dff292a3d447e0bfafa61015d64.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1326; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=CInTZPEi9ILbXu4UpfN2lm4dHyQfqcOZ4rC45zzBAr0=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGvuVHhy9KbbDsPkpU2r9d8dfDpFfuKFsmQW9hDDq 7e3FvL/6ShlYRDjYpAVU2Q5/p9714yuL6n5U3fpw8xhZQIZwsDFKQATmZ3D8L9C6W/6lK8J3p37 lbyv2GhNrn45dU+58XqlPZUHVdpNs8UY/tmG9ys7NYupMV914dmx7f0fh8UnP02okW3kXffjuZD ZP0YA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Following patch will add missing barrier_nospec() to copy_from_user_iter(). Avoid it for architectures supporting masked user accesses, the same way as done for copy_from_user() by commit 0fc810ae3ae1 ("x86/uaccess: Avoid barrier_nospec() in 64-bit copy_from_user()") Signed-off-by: Christophe Leroy --- v2: New in v2 --- lib/iov_iter.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 2fe66a6b8789e..a589935bf3025 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -49,12 +49,16 @@ size_t copy_from_user_iter(void __user *iter_from, size= _t progress, =20 if (should_fail_usercopy()) return len; - if (access_ok(iter_from, len)) { - to +=3D progress; - instrument_copy_from_user_before(to, iter_from, len); - res =3D raw_copy_from_user(to, iter_from, len); - instrument_copy_from_user_after(to, iter_from, len, res); - } + if (can_do_masked_user_access()) + iter_from =3D mask_user_address(iter_from); + else if (!access_ok(iter_from, len)) + return res; + + to +=3D progress; + instrument_copy_from_user_before(to, iter_from, len); + res =3D raw_copy_from_user(to, iter_from, len); + instrument_copy_from_user_after(to, iter_from, len, res); + return res; } =20 --=20 2.49.0