From mboxrd@z Thu Jan 1 00:00:00 1970 From: Coly Li Subject: Re: [PATCH v4 3/3] lib/test_crc: Add test cases for crc calculation Date: Wed, 25 Jul 2018 00:28:15 +0800 Message-ID: <2feeece1-6d92-aa08-c9b6-1b0c646eed29@suse.de> References: <20180718165545.1622-1-colyli@suse.de> <20180718165545.1622-4-colyli@suse.de> <20180724044420.GB1944@sol.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180724044420.GB1944@sol.localdomain> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Eric Biggers Cc: linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, Greg Kroah-Hartman , Linus Torvalds , Thomas Gleixner , Kate Stewart , Andrew Morton , Randy Dunlap , Andy Shevchenko , Noah Massey List-Id: linux-bcache@vger.kernel.org On 2018/7/24 12:44 PM, Eric Biggers wrote: > On Thu, Jul 19, 2018 at 12:55:45AM +0800, Coly Li wrote: >> This patch adds a kernel module to test the consistency of multiple crc >> calculation in Linux kernel. It is enabled with CONFIG_TEST_CRC enabled. >> >> The test results are printed into kernel message, which look like, >> >> test_crc: crc64_be: FAILED (0x03d4d0d85685d9a1, expected 0x3d4d0d85685d9a1f) >> >> kernel 0day system has framework to check kernel message, then the above >> result can be handled by 0day system. If crc calculation inconsistency >> happens, it can be detected quite soon. >> >> lib/test_crc.c is a testing frame work for many crc consistency >> testings. For now, there is only one test caes for crc64_be(). > > Are you aware there's already a CRC-32 test module: CONFIG_CRC32_SELFTEST and > lib/crc32test.c? Confusingly, your patch uses a different naming convention for > the new CRC-64 one, and puts the Kconfig option in a different place, and makes > it sound like it's a generic test for all CRC implementations rather than just > the CRC-64 one. Please use the existing convention (i.e. add > CONFIG_CRC64_SELFTEST and lib/crc64test.c) unless you have a strong argument for > why it should be done differently. > > (And I don't think it makes sense to combine all CRC tests into one module, > since you should be able to e.g. enable just CRC32 and CRC32_SELFTEST without > also pulling in a dependency on all the other CRC variants.) > Hi Eric, The purpose of test_crc is to provide a unified crc calculation consistency testing for 0day. So far it is only crc64, and I will add more test cases later. I see there is crc-32 test module, which does more testing then consistency check, and no unified format for 0day system to detect. This is why people suggested me to add this test framework. >> +/* Add your crc test cases here */ >> +static void test_crc64_be(struct crc_test_record *rec) >> +{ >> + u64 crc; >> + >> + crc = crc64_be(rec->initval, rec->data, sizeof(rec->data)); >> + chk_and_msg(rec->name, crc, rec->expval); >> +} >> + >> +/* >> + * Set up your crc test initial data here. >> + * Do not change the existing items, they are hard coded with >> + * pre-calculated values. >> + */ >> +static struct crc_test_record test_data[] = { >> + { .name = "crc64_be", >> + .data = { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26, >> + 0xC711223CFA3E5BB5, 0x493366450E42ECDF }, >> + .initval = 0x61C8864680B583EB, >> + .expval = 0xb2c863673f4292bf, >> + .handler = test_crc64_be, >> + }, >> + {} >> +}; > > This is incorrect; the test is checksumming data that has a CPU-specific > endianness. So, it will fail on big-endian systems. The data needs to be > declared as a byte or char array instead. See e.g. what crypto/testmgr.h does > for crypto API algorithms. > > Also please mark the test data structures 'const'. Sure, I will send fix patches (not rebase the posted patches because they are in linux-next for now) soon. Thanks for your comments. Coly Li