From patchwork Mon Aug 29 07:56:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Feng Tang X-Patchwork-Id: 12957486 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 08C71ECAAD5 for ; Mon, 29 Aug 2022 07:55:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1B27D940008; Mon, 29 Aug 2022 03:55:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1639D940007; Mon, 29 Aug 2022 03:55:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 02A6B940008; Mon, 29 Aug 2022 03:55:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id E89FB940007 for ; Mon, 29 Aug 2022 03:55:49 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 92116409FE for ; Mon, 29 Aug 2022 07:55:49 +0000 (UTC) X-FDA: 79851871218.19.49A452F Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf20.hostedemail.com (Postfix) with ESMTP id 8B36D1C0016 for ; Mon, 29 Aug 2022 07:55:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1661759747; x=1693295747; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=GIoiXdJvmXZ6xSeL3NAMSUDFWyLW73E9SMskZ4AWliI=; b=gYKzkt21BsbFcL3whpN0l5y+1rphV/eEXZHhSUP+DginBOnm+wLmDalP DCfyojNaOVoDD8JDo0WkuZe6BJrwOVecE8DvW36PvUQmkEMVsvKIOpTi6 g7pB2iNcKhGZPamUwZhYQpNwhn3EtmqlQwq541Ooy6M7C+z9OCpRqOFGP I7h8XIsKYntjqN1ELzR6PZCI7ZTPp8oV0XjqwxX+gXjXtTDFfUegnn3pA QWa+VEu+KLZjZmCQ1pQgUi4LF5rnNNIscJM/ZkBMz2ivCPFx1KGtZxr/o w0dP5W75ia35cZaJy1v2J0ssjlpknWpuaqtRkScqfX0eg+LVfqmGsh9tf g==; X-IronPort-AV: E=McAfee;i="6500,9779,10453"; a="296111499" X-IronPort-AV: E=Sophos;i="5.93,272,1654585200"; d="scan'208";a="296111499" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2022 00:55:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,272,1654585200"; d="scan'208";a="672283525" Received: from shbuild999.sh.intel.com ([10.239.147.181]) by fmsmga008.fm.intel.com with ESMTP; 29 Aug 2022 00:55:42 -0700 From: Feng Tang To: Andrew Morton , Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Dmitry Vyukov Cc: Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Feng Tang Subject: [PATCH v4 0/4] mm/slub: some debug enhancements for kmalloc objects Date: Mon, 29 Aug 2022 15:56:14 +0800 Message-Id: <20220829075618.69069-1-feng.tang@intel.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661759748; a=rsa-sha256; cv=none; b=mgvogawoJap5BxJoVsd/15NdByb7zupMDifo3mJ0Ji9oIgIdgFaHX2OPtB3Run7R6Lp0qu BFuXX8RHpA6rI5SI9inVMJU2t8RLrkP+2aA7/7NwSeYu0TQnvCemP9djtaku/WlFUyG5Ii 1bo+64CThcGFXAIpzNLi68ItnaLOXgc= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=gYKzkt21; spf=pass (imf20.hostedemail.com: domain of feng.tang@intel.com designates 134.134.136.65 as permitted sender) smtp.mailfrom=feng.tang@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661759748; 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-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=F6YOOrD5ErAkSEgnNwBCc7ZSnEP651AmurZ8NY+HV04=; b=nBmO2gKg9cszVBhfCpqKtdLaj4vKsnsZYd1sD/JdAzN9ERaQbcam1OmYRnnbvie5STyICt 7PfDavepk05hyPUr+njhSNSIZYIhQIV3Izy/Ozz8ZMYJczawEW80DdZQE9UIaxkK5Yhccp Av1s2hYKS3GdveKzv2B5Cf0axid903A= X-Rspam-User: X-Rspamd-Queue-Id: 8B36D1C0016 Authentication-Results: imf20.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=gYKzkt21; spf=pass (imf20.hostedemail.com: domain of feng.tang@intel.com designates 134.134.136.65 as permitted sender) smtp.mailfrom=feng.tang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Stat-Signature: ee1o4tz7a6whphs6p4nok4xygab5bu9r X-Rspamd-Server: rspam07 X-HE-Tag: 1661759747-416543 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: kmalloc's API family is critical for mm, and one of its nature is that it will round up the request size to a fixed one (mostly power of 2). When user requests memory for '2^n + 1' bytes, actually 2^(n+1) bytes could be allocated, so in worst case, there is around 50% memory space waste. The wastage is not a big issue for requests that get allocated/freed quickly, but may cause problems with objects that have longer life time, and there were some OOM cases in some extrem cases. This patchset tries to : * Add a debug method to track each kmalloced object's wastage info, and show the call stack of original allocation (depends on SLAB_STORE_USER flag) * Extend the redzone sanity check to the extra kmalloced buffer than requested, to better detect un-legitimate access to it. (depends on SLAB_STORE_USER & SLAB_RED_ZONE) The redzone part has been tested with code below: for (shift = 3; shift <= 12; shift++) { size = 1 << shift; buf = kmalloc(size + 4, GFP_KERNEL); /* We have 96, 196 kmalloc size, which is not power of 2 */ if (size == 64 || size == 128) oob_size = 16; else oob_size = size - 4; memset(buf + size + 4, 0xee, oob_size); kfree(buf); } Please help to review, thanks! - Feng --- Changelogs: since v3: * rebase against latest post 6.0-rc1 slab tree's 'for-next' branch. * fix a bug reported by 0Day, that kmalloc-redzoned data and kasan's free meta data overlaps in the same kmalloc object data area since v2: * rebase against slab tree's 'for-next' branch * fix pointer handling (Kefeng Wang) * move kzalloc zeroing handling change to a separate patch (Vlastimil Babka) * make 'orig_size' only depend on KMALLOC & STORE_USER flag bits (Vlastimil Babka) since v1: * limit the 'orig_size' to kmalloc objects only, and save it after track in metadata (Vlastimil Babka) * fix a offset calculation problem in print_trailer since RFC: * fix problems in kmem_cache_alloc_bulk() and records sorting, improve the print format (Hyeonggon Yoo) * fix a compiling issue found by 0Day bot * update the commit log based info from iova developers Feng Tang (4): mm/slub: enable debugging memory wasting of kmalloc mm/slub: only zero the requested size of buffer for kzalloc mm: kasan: Add free_meta size info in struct kasan_cache mm/slub: extend redzone check to cover extra allocated kmalloc space than requested include/linux/kasan.h | 2 + include/linux/slab.h | 2 + mm/kasan/common.c | 2 + mm/slab.c | 6 +- mm/slab.h | 13 +++- mm/slab_common.c | 4 + mm/slub.c | 168 +++++++++++++++++++++++++++++++++++++----- 7 files changed, 172 insertions(+), 25 deletions(-)