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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B19BC04A68 for ; Wed, 27 Jul 2022 07:10:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230091AbiG0HKw (ORCPT ); Wed, 27 Jul 2022 03:10:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229927AbiG0HKk (ORCPT ); Wed, 27 Jul 2022 03:10:40 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8BFEE088 for ; Wed, 27 Jul 2022 00:10:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658905839; x=1690441839; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=pgzWF10gM+nk0heJ6laSiJKJPMsfPIgqqxGgbJXgLcM=; b=QNtVcMDXswsVAiUrWsTAZMHKSyWf3s5YR+JOVrlM34vQmkb+/UMonX1R O0AvbJZjcOD76WEtGzoefnwXRmv/bxGJQobUjhOmDQ2PUDeN+9U+R9hZ3 bVMO2OyREow/eer53n9c5RqqZeRvaqzRovuO/1TqO6m86yl2AQjmsXtwC f9LVMdZYVafu4mOkV9kFd6IL16L2DORgWiRtuXsLQ9cwfZ8nLZRleIY0p MQ7sf49gJZHyhppEC2i8+lYs27nAWqa4Qnp6yqvq92g6kbt4FXe0TnJxQ NUov3GyTkN3d7GwJbmJ6fyCykhEvVWtbxrrd656U9pXMS1tJ7jb3tBmp0 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10420"; a="267931675" X-IronPort-AV: E=Sophos;i="5.93,195,1654585200"; d="scan'208";a="267931675" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jul 2022 00:10:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,195,1654585200"; d="scan'208";a="550737896" Received: from shbuild999.sh.intel.com ([10.239.146.138]) by orsmga003.jf.intel.com with ESMTP; 27 Jul 2022 00:10:35 -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>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Dave Hansen , Robin Murphy , John Garry , Kefeng Wang , Feng Tang Subject: [PATCH v3 0/3] mm/slub: some debug enhancements Date: Wed, 27 Jul 2022 15:10:39 +0800 Message-Id: <20220727071042.8796-1-feng.tang@intel.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 * Extend the redzone sanity check to the extra kmalloced buffer than requested, to better detect un-legitimate access to it. Please help to review, thanks! - Feng --- Changelogs: since v2: * rebased 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 (3): mm/slub: enable debugging memory wasting of kmalloc mm/slub: only zero the requested size of buffer for kzalloc mm/slub: extend redzone check to cover extra allocated kmalloc space than requested include/linux/slab.h | 2 + mm/slab.c | 8 +-- mm/slab.h | 9 ++- mm/slub.c | 157 ++++++++++++++++++++++++++++++++++++------- 4 files changed, 146 insertions(+), 30 deletions(-) -- 2.27.0