From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 BF2C01757A; Wed, 3 Apr 2024 22:45:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712184355; cv=none; b=XV0ZlqXRhdSpHd2bUCoC3QzVordKlsrMX68mi6jVa5hqmYJv81sb7VuTMHMomPcCrR/bxWis5DQ5kEqmfZl9aCuGw8UYaMzHS0R5Wu7KqpfmbtPSOy+UkTMK1CuLyHYmqwhjX1kvwA4hAV2N6A37m5KGQ/GO428FbKA5m8LSDQE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712184355; c=relaxed/simple; bh=Wl13HCQUnod0lTUKQ6DNuqqLHcv1UPBQ6Mocvat/Q3E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OrH3uBCPSMVU0Ltm9TKU9jkyIxQHhV4Y0cuZrRrQqRkg3S5vpgWyzsR8A3gE8Em9iaZIZ+kfpGfcGkEQEJHAbkQKiVJz911ZjXkUSLlUWP8xlWS/L4ZnoWdWMP9+RnRuWGBFx4LyxOEYDa2MlNOJ3XWc+Wz4mdvX6JwPMDpwkqw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=t2ncr//f; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="t2ncr//f" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=zlKZnL7sDm8BDCMejJeZM50ZtuMxH0tQsMbjPb3yHD8=; b=t2ncr//fpGvPtpESJNxRb6/ovo c8kDk5LFRDFeqtIIPAWZbXg37VJMBMuLM/WrbBwybND37YVoNxDknuqeN4Xzx4n0yyAeyzIpXpD8n aRVrbdxNoGlYBges4TbCTHcW+TYHr5QBZYfmd/uYwq6HaTcmvZlvePB78sLuJFjRgp6/6R0bxL2nF QFdzEU0ksQQEYlIl4+vky3ogrI2/xGnyFkZMmoVNm7SiLB5q72L5gfUKSC/wxWD8fSciZFOQJtuYD Vzc2GB6F6rX/U93Bbdlsfwg1coD6Hc0w4G9ooDWlpfQe/RkjSnuy3VTFTdUqRruF87O2IGYqfJLC7 4hfCSTGQ==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1rs9Md-005Bdo-27; Wed, 03 Apr 2024 22:45:51 +0000 Date: Wed, 3 Apr 2024 23:45:51 +0100 From: Al Viro To: Jens Axboe Cc: linux-fsdevel@vger.kernel.org, brauner@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] userfaultfd: convert to ->read_iter() Message-ID: <20240403224551.GN538574@ZenIV> References: <20240403140446.1623931-1-axboe@kernel.dk> <20240403140446.1623931-3-axboe@kernel.dk> 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: <20240403140446.1623931-3-axboe@kernel.dk> Sender: Al Viro On Wed, Apr 03, 2024 at 08:02:53AM -0600, Jens Axboe wrote: > - if (count < sizeof(msg)) > + if (iov_iter_count(to) < sizeof(msg)) > return ret ? ret : -EINVAL; > _ret = userfaultfd_ctx_read(ctx, no_wait, &msg, inode); > if (_ret < 0) > return ret ? ret : _ret; > - if (copy_to_user((__u64 __user *) buf, &msg, sizeof(msg))) > + _ret = copy_to_iter(&msg, sizeof(msg), to); > + if (_ret < 0) > return ret ? ret : -EFAULT; Take a look in uio.h - you'll see size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) in there. See the problem? > + fd = get_unused_fd_flags(O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS)); > + if (fd < 0) > + goto err_out; Same comment as for the previous patch.