From patchwork Wed Sep 7 07:10:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Feng Tang X-Patchwork-Id: 12968508 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 35CCCC38145 for ; Wed, 7 Sep 2022 07:10:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 44CDC6B0072; Wed, 7 Sep 2022 03:10:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3FBFE8D0003; Wed, 7 Sep 2022 03:10:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C5748D0002; Wed, 7 Sep 2022 03:10:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 1FDC46B0072 for ; Wed, 7 Sep 2022 03:10:52 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id E7BB0C0F13 for ; Wed, 7 Sep 2022 07:10:51 +0000 (UTC) X-FDA: 79884417102.26.7734D0F Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf19.hostedemail.com (Postfix) with ESMTP id E621C1A005A for ; Wed, 7 Sep 2022 07:10:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662534651; x=1694070651; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=yDo54Ene97KfLAtM/nTSGuxis/RqzNhE541Fy1Mc1ok=; b=Ej4nw5fqMruhqMukceAX9t/ssFXcy+et3rhP+7pIt28de1isqMoVslXL zwQqI8fTxQQ9r06KgINLDMxUvPlbFFDJy1Y/RCu74FKWQXSGljNyC5aVg C0ULJ8T4/2V1W0iMNdR9Ewssm31UfCG/qkRPvE1XSlGCT37acyf7S8gqA MHjen2XgSsYoT9aTFxgNns7YN937QnhbQ6NRR8tVK0V42W00+BiMsBK/7 /NXjFGa1K2Mr2JYo3LlaT6WVv2OueyvcF0eS+VSDwvsdrt4tWedlQr6k1 +9YL2gOL1lPE4Qe135KHeSswPL5vRgLlJ0dm+n6KER1gjDcp1Yc59TG7b w==; X-IronPort-AV: E=McAfee;i="6500,9779,10462"; a="283798242" X-IronPort-AV: E=Sophos;i="5.93,296,1654585200"; d="scan'208";a="283798242" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2022 00:10:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,296,1654585200"; d="scan'208";a="676053353" Received: from feng-clx.sh.intel.com ([10.238.200.228]) by fmsmga008.fm.intel.com with ESMTP; 07 Sep 2022 00:10:45 -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 , Jonathan Corbet Cc: Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Feng Tang Subject: [PATCH v5 0/4] mm/slub: some debug enhancements for kmalloc Date: Wed, 7 Sep 2022 15:10:19 +0800 Message-Id: <20220907071023.3838692-1-feng.tang@intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=Ej4nw5fq; spf=pass (imf19.hostedemail.com: domain of feng.tang@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=feng.tang@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662534651; a=rsa-sha256; cv=none; b=UkSWCG8PMovUIdxQmUCtguzSRnsw1K9UJnUY6P1LAA0H2dOD10kEOCa/AdAbDVSuQJEeFf RevyK5WHjJzb2WE47z5qnEMuBtLsB2cFfxtW8eck0qBRDv8O6BQibkMz86wGxiXyaxfUGB +7zp6VNgSv1q2Q8uR0Y1HyHagSqVSX0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662534651; 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=7vGaJ+8rR4sKenXyQevhftma18DmMyFcMlRG/iZVWcM=; b=B2o/byWONswYCrjgcR9dJ9G9z6zBmJYLutPMNKmYvgcfbqrGTRVYdS1JQBa5FKb4SSv/eM VxwUbf0OS0G9yLVEkWadx12kT9ahXT3DHTJMll0cEYPTBV3twx/7IANJUI22hK6gtmhf8x fUjaWMSvEJPppcDQ6imp8tCvRW4SlN0= Authentication-Results: imf19.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=Ej4nw5fq; spf=pass (imf19.hostedemail.com: domain of feng.tang@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=feng.tang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Stat-Signature: 7e77r5cq5iyrcfrirdpg1iu8qxum6kxx X-Rspamd-Queue-Id: E621C1A005A X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1662534650-640236 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 v4: * fix a race issue in v3, by moving kmalloc debug init into alloc_debug_processing (Hyeonggon Yoo) * add 'partial_conext' for better parameter passing in get_partial() call chain (Vlastimil Babka) * update 'slub.rst' for 'alloc_traces' part (Hyeonggon Yoo) * update code comments for 'orig_size' 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 extra allocated kmalloc space than requested Documentation/mm/slub.rst | 33 +++--- 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 | 219 ++++++++++++++++++++++++++++++-------- 8 files changed, 220 insertions(+), 61 deletions(-)