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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 12F78C531CC for ; Sun, 26 Jul 2026 07:03:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E27476B0088; Sun, 26 Jul 2026 03:03:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DD8156B008A; Sun, 26 Jul 2026 03:03:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D15686B008C; Sun, 26 Jul 2026 03:03:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id AA1A16B0088 for ; Sun, 26 Jul 2026 03:03:40 -0400 (EDT) Received: from smtpin05.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 0E889120496 for ; Sun, 26 Jul 2026 07:03:40 +0000 (UTC) X-FDA: 85030037400.05.CB038FA Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf14.hostedemail.com (Postfix) with ESMTP id 784BD100006 for ; Sun, 26 Jul 2026 07:03:38 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=dUF2MOdz; spf=pass (imf14.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785049418; 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=kdbLcjl6WNvMUmGYANLJvd5g9DECNaym80X7NqFHU+M=; b=gCkbGvaZp393+rtuX4U3/wx4NX6Zigd9r1XXmxacHK/95cICephHKRrjSLyMhiHlpuv6k7 OfGbmWqsWnrf0MrUsk4aSjetWnySBm8VByNv2nXWZBT63ElHZRQvrHdXLm5GSchbYHhclS 4XI3M/tbiKbF15Jt69JtdAPzuwYlgCk= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=dUF2MOdz; spf=pass (imf14.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785049418; b=rrGN65RFNuLPEftiF07Q7OV//4DciV37XBeFwgeVrJyUn662csToDRjHgMRrxjSZFHKknC ZDott51Ih9JU/vKTwSMunm5F3300Z04rL6hNfrqNkfv9MvcuzK957Hky0sqOV9hRxnk5WO /9zZz9M4D0OJYeQkeN67ZTY3mwIDg3g= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id C204D431F8; Sun, 26 Jul 2026 07:03:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58B461F000E9; Sun, 26 Jul 2026 07:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785049417; bh=kdbLcjl6WNvMUmGYANLJvd5g9DECNaym80X7NqFHU+M=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=dUF2MOdzwq29dVuE0ufR2hlhLRTSkFOdEtXya6XFYfWR7QHSQNzFoD32jNwdCf3Kq mB6OqBKncVTSu5dFUFnbGs5ZcdzLpU5Ri2uIfrMsPnYnuMxO5Y1/C3telAMQgKKqFA S81qCQRPfJ/rQdmr1b6b0UX0kg+/gt73Y8SkljMOJbZBiK4eSnW4CELQMUSj/zIQWY arcNBa3A639yqKLFtCr1G8Y8dr4XIsbYFYy1PQ5iGZ2WiQBlZlYLUdAXllTpUzF8AI 7mWGsfUqYhjqQGNOD18uVkB0nx5b9sxKDGRce/UR7lqy4H67tq32/fY0UVKcxkl9Yu kmZjsrYrhBbHA== Date: Sun, 26 Jul 2026 10:03:31 +0300 From: Mike Rapoport To: Mahad Ibrahim Cc: Kees Cook , Arnd Bergmann , Greg Kroah-Hartman , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] lkdtm: use kmalloc() instead of __get_free_page Message-ID: References: <20260722230246.2869-1-mahad.ibrahim.dev@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260722230246.2869-1-mahad.ibrahim.dev@gmail.com> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 784BD100006 X-Stat-Signature: szjkjoyawpzpsjzuq36zf3tirzsf9ton X-HE-Tag: 1785049418-156436 X-HE-Meta: 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 bXRstGBK +ZQ38qB7yKDW74Hlon3YmkJWyTnzZvw7v/yxIWnhvp2vbCnTEbgnwNOyqLDJM+s6cxN026vGY0V35seulwygYLhttgoYp1wVT3zeXBACc1DGvXrLuZWYGsGtZ8Vg0mb/6xzk2g0nlHQpQNjQWrbjIT3blNAIULHdux2J2R3RXyWwPOlWcUb6JsGEnBp3zewD2+PpryBdXFvyyAi2rZh7yJ1av1EVc18lgsAiKDdPt85s2DywZ1NNf6WM8eBCmBr/7m7jICDeqX5dQ8J3f+//hsvds+5HS/PhYObcZ2cwLBJiBFuOjXQ9MqAnN6kJLgsIdqqohXUoOYgjbvFFxYx+vhrcGV4VpAMfyhV1b8MYwC1nCA4mjzRjIagKzBSOMbyV0xvHaQbdXwdds0qxzEYb8Y8+vd2BQzDWoWNspPSCtJ60D1Es= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jul 22, 2026 at 11:02:46PM +0000, Mahad Ibrahim wrote: > lkdtm_debugfs_entry and direct_entry use __get_free_page to allocate a > temporary buffer, perform copy_from_user to get the crashtype name, > strim() to strip whitespace and find_crashtype to find the corresponding > crashtype that is being requested. > > The lkdtm_debugfs_read uses __get_free_page to allocate a temporary > buffer to store all the available crashtypes, and then copy it to > userspace. > > The buffers that are allocated can be allocated with kmalloc as there is > nothing special that requires a struct page, or the page allocator. > > kmalloc() additionally provides a better API that doesn't require ugly > casts which obfuscate the code and kfree does not need to know the size > of the freed object. > > Replace use of __get_free_page() with kmalloc(). > > Signed-off-by: Mahad Ibrahim Acked-by: Mike Rapoport (Microsoft) > --- > drivers/misc/lkdtm/core.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) -- Sincerely yours, Mike.