Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v3 3/3] lib/test_crc: Add test cases for crc calculation
To:     Noah Massey <noah.massey@gmail.com>
Cc:     linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org,
        linux-block@vger.kernel.org, gregkh@linuxfoundation.org,
        torvalds@linux-foundation.org, tglx@linutronix.de,
        kstewart@linuxfoundation.org
References: <20180717145525.50852-1-colyli@suse.de>
 <20180717145525.50852-4-colyli@suse.de>
 <CADfjVriarrPnxixjun1g0m7izp4kMCvP4vXuPtNTth7_LWXrMA@mail.gmail.com>
From:   Coly Li <colyli@suse.de>
Openpgp: preference=signencrypt
Autocrypt: addr=colyli@suse.de; prefer-encrypt=mutual; keydata=
 xsFNBFYX6S8BEAC9VSamb2aiMTQREFXK4K/W7nGnAinca7MRuFUD4JqWMJ9FakNRd/E0v30F
 qvZ2YWpidPjaIxHwu3u9tmLKqS+2vnP0k7PRHXBYbtZEMpy3kCzseNfdrNqwJ54A430BHf2S
 GMVRVENiScsnh4SnaYjFVvB8SrlhTsgVEXEBBma5Ktgq9YSoy5miatWmZvHLFTQgFMabCz/P
 j5/xzykrF6yHo0rHZtwzQzF8rriOplAFCECp/t05+OeHHxjSqSI0P/G79Ll+AJYLRRm9til/
 K6yz/1hX5xMToIkYrshDJDrUc8DjEpISQQPhG19PzaUf3vFpmnSVYprcWfJWsa2wZyyjRFkf
 J51S82WfclafNC6N7eRXedpRpG6udUAYOA1YdtlyQRZa84EJvMzW96iSL1Gf+ZGtRuM3k49H
 1wiWOjlANiJYSIWyzJjxAd/7Xtiy/s3PRKL9u9y25ftMLFa1IljiDG+mdY7LyAGfvdtIkanr
 iBpX4gWXd7lNQFLDJMfShfu+CTMCdRzCAQ9hIHPmBeZDJxKq721CyBiGAhRxDN+TYiaG/UWT
 7IB7LL4zJrIe/xQ8HhRO+2NvT89o0LxEFKBGg39yjTMIrjbl2ZxY488+56UV4FclubrG+t16
 r2KrandM7P5RjR+cuHhkKseim50Qsw0B+Eu33Hjry7YCihmGswARAQABzRhDb2x5IExpIDxj
 b2x5bGlAc3VzZS5kZT7CwX8EEwEIACkFAlYX6ZACGyMFCQlmAYAHCwkIBwMCAQYVCAIJCgsE
 FgIDAQIeAQIXgAAKCRDHOQeTa334/CncD/9B97EIjcDOm0TS164bpMlsbZWEm8GQnV6nVzm8
 QsywPRM8S8nqkqX1atTYl/fTdJsasH8mgryUqL0eHBPs5RmJhDk3YgYsTrzbOjMdsdRwv24W
 J5RXdulRag2XDPIhSP7rWsOSh66gljdAp8XQQZD0zFXi4IytoAuLtx8RMjzzKk1iP6uz8MIv
 em7iFu6NYcHd3cmvSPo7CnBVaG0dZ6P2p2gS7ydSWOGsWkNh/XM4ojJaX1ZdCeFR0XLS76Gi
 6e01DoN2UsqZE/TQu1czYMMA1uM/Es6ZTYgobTrrnNB79ctqgtbBrjME5sOHLX40ccbBI3QB
 Ta4opSp8VqUMXw/yd5ckLPocnkJBTVxuaOfRhpxr6gWeudrkMetMj+39yeklskP7up0JvAUG
 7/HjjqwWR7xAaZHmZORYsIxJ9ploBb8eSqHHx+7489ZDNLP+WCsAonpKTdJNAzGJClnLFxKS
 DY4cOPs7o4IFBk6dVXJWMqyLGwmMQ51Pq6BID4epaAuuBAL6x7n7NrFPuS68Fn/VaxqMEld9
 L2eCi4cv++1AJyMF3iQKT56I8BjHEuf0wo1tmZ3BgBT19xRsEl7YItixxtYQm66Pb4lSQQmE
 Ep+uQNwaqPpeAU+vkDg/0Q+dhPTsvwx0OAI30HwhuzNA8OIfHBx7dJNm0b0fg5x0pg3LDM7B
 TQRWF+kvARAA2T/tnJeA0RWkmgZrNPFvP7JnOU9gjmIQKMoGZ+9awew45pdmXb6y0Y0fEG59
 EP9i9oBlFXOt6SZ2645V0sdi3wBRNEpX2CCddWhXRfcO0b6lgckIwyaK92dH1rzxMaZTYDL8
 aQ9FNEK1U+XSBk8fYWnXowpf7oNPS6+jD0J/muPqrGkVsIAkh2iLg5B98yNTCV4ql1xSlMyf
 xcseke9q6ojDxx9p38JjLusDlwF2+/rF42c+T6PRiYNjnBHPq6VLSlCRsnkLJwg8VHKiV2Qw
 Yvxp4TwnK2kLqokOxBlriX45Odb2iP61uG2ZAPchDwfawWJ4G8+3EMplLH8bk0/DkpYcYz95
 eGSGRSiIQ2kHmTI/KbpgXxFVMoheilUn4HzUP+T6TEeP6Zhm0aqwABJYa0T2ykJwpBlg6/Mx
 vgIzdSheqx2hYACDu07WfhdvI6uK3i5Lq9DebUBcMMBcMc0TnXix7mYy+3hLXJzZ80pFx3My
 5FeJEN/r6/+xpuuZkH51aYOiacKVa2w2EHjhZcWfPhhEWOQ2oOCoCmv+HEmV9sf+fipEMfcB
 8GnJMOYAwrwHWfkPNZ5urUcRGAQYlQ0GWKju97LYE2cq5McpFG0CMvDyPoO1zAwjJz4g53EK
 oH/eikd3L8OMDfEK4AOsUaPMTnNgt1+40zEFMrQs/dDMldUAEQEAAcLBZQQYAQgADwUCVhfp
 LwIbDAUJCWYBgAAKCRDHOQeTa334/PtREACDN8W/pHeHyPW/mTt6MEe/GICG5YdlBW5ft7HY
 Cf6rTz+uLZolGc5SYKuJJ0JC/L2Ifh3BWmwLIOxV868KB3oEfmGszBY+4n/icLyIEAkkthBb
 2V5sP5KgB3bOg7mSFBxfHi2pyO9K9d+Lr+UkORjCGyV33QFrcN+OQdPDactontnQglB7xm2K
 phGWqxoqepHCqFIulZ3yKGhQhmdpyz0J19Ry6GkxPE85MG/NC98D5+4Yn/V3G+yZpbGsuFhE
 CP26JvdXh1jNCUdU46pEjZwu0GXBIo6r1cb1v+swfYB86NeFUHWtvxamh8i6RBl1FLDhN6xb
 r9f7M++xoADyzPQYQPQUxWK+iG6lz3qVVq5312z/is3fcdyESPNs09DMT43xCCBr9UOMq6dZ
 IC9EsSeMYv4librfuSRqH4R0MuVbVWLJFg/Q7s+nbPb2YjhqIYr51hBDyXpzUDoIz43maIPk
 UmCNKa43mNFktMrwU21J5lVXEwBuTY6JlHOAl0Fgo28X+eTa8fx2Uiz9OVgWe03ebJGIGowe
 XTgqVWJMsKM1tmW+QFmgtczDGRYCZ6OQYpqt0SoTg1yx5MN4RzUtlLka2qLfPiOGUUN3qNJ5
 nP+spvF+s+dHtLjjhy7AL86N01a6S0rwaClVVv0XTucvIntwccIx0CZfUKlfn5BWnB64Ig==
Message-ID: <fbabeaad-cf55-223e-2a6c-682987f676bf@suse.de>
Date:   Wed, 18 Jul 2018 23:28:13 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0)
 Gecko/20100101 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <CADfjVriarrPnxixjun1g0m7izp4kMCvP4vXuPtNTth7_LWXrMA@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2018/7/18 2:51 AM, Noah Massey wrote:
> On Tue, Jul 17, 2018 at 10:56 AM Coly Li <colyli@suse.de> 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: PASSED (0x4e6b1ff972fa8c55, expected 0x4e6b1ff972fa8c55)
>> test_crc: crc64_bch: PASSED (0x0e4f1391d7a4a62e, expected 0x0e4f1391d7a4a62e)
>> test_crc: crc64_update: 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 are only test caes for 3 crc routines,
>> - crc64()
>> - crc64_bch()
>> - crc64_update()
>>
>> Changelog:
>> v3: Add test cases passed/failed statistic
>>     More fixes for review comments of v2
>> v2: Fixes for review comments of v1
>> v1: Initial version.
>>
>> Signed-off-by: Coly Li <colyli@suse.de>
>> Reviewed-by: Hannes Reinecke <hare@suse.de>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Kate Stewart <kstewart@linuxfoundation.org>
>> ---
>>  lib/Kconfig.debug |  10 ++++
>>  lib/Makefile      |   1 +
>>  lib/test_crc.c    | 138 ++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 149 insertions(+)
>>  create mode 100644 lib/test_crc.c
>>
>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>> index 8838d1158d19..a9c1de0c2a7d 100644
>> --- a/lib/Kconfig.debug
>> +++ b/lib/Kconfig.debug
>> @@ -1911,6 +1911,16 @@ config TEST_SYSCTL
>>
>>           If unsure, say N.
>>
>> +config TEST_CRC
>> +       tristate "CRC calculation test driver"
>> +       depends on CRC64
>> +       help
>> +         This builds the "test_crc" module. This driver enables to test the
>> +         CRC calculation consistency to make sure new modification does not
>> +         break existing checksum calculation.
>> +
>> +         if unsure, say N.
>> +
>>  config TEST_UDELAY
>>         tristate "udelay test driver"
>>         default n
>> diff --git a/lib/Makefile b/lib/Makefile
>> index 40c215181687..224d047d026a 100644
>> --- a/lib/Makefile
>> +++ b/lib/Makefile
>> @@ -49,6 +49,7 @@ obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o
>>  obj-$(CONFIG_TEST_BPF) += test_bpf.o
>>  obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
>>  obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
>> +obj-$(CONFIG_TEST_CRC) += test_crc.o
>>  obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o
>>  obj-$(CONFIG_TEST_KASAN) += test_kasan.o
>>  CFLAGS_test_kasan.o += -fno-builtin
>> diff --git a/lib/test_crc.c b/lib/test_crc.c
>> new file mode 100644
>> index 000000000000..441bf835fbd3
>> --- /dev/null
>> +++ b/lib/test_crc.c
>> @@ -0,0 +1,138 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * CRC test driver
>> + *
>> + * Copyright (C) 2018 Coly Li <colyli@suse.de>
>> + *
>> + * This module provides an simple framework to check the consistency of
>> + * Linux kernel CRC calculation routines in lib/crc*.c. This driver
>> + * requires CONFIG_CRC* items to be enabled if the associated routines are
>> + * tested here. The test results will be printed to kernel message
>> + * when this test driver is loaded.
>> + *
>> + * Current test routines are,
>> + * - crc64()
>> + * - crc64_bch()
>> + * - crc64_update()
>> + *
>> + */
>> +
>> +#include <linux/async.h>
>> +#include <linux/delay.h>
>> +#include <linux/fs.h>
>> +#include <linux/list.h>
>> +#include <linux/module.h>
>> +#include <linux/printk.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/slab.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/crc64.h>
>> +
>> +struct crc_test_record {
>> +       char    *name;
>> +       u64     data[4];
>> +       u64     initval;
>> +       u64     expval;
>> +       int     (*handler)(struct crc_test_record *rec);
>> +};
>> +
>> +static int chk_and_msg(const char *name, u64 crc, u64 expval)
>> +{
>> +       int ret = 0;
>> +
>> +       if (crc == expval) {
>> +               pr_info("test_crc: %s: PASSED:(0x%016llx, expected 0x%016llx)\n",
>> +                       name, crc, expval);
> 
> I don't think we should have specific kernel output for passed tests.
> If a new test is added which follows this pattern, the 0-day will fail
> because the kernel output would change. Along the lines of "silence is
> golden", if no test hit the error output, we're good.
> 
>> +       } else {
>> +               pr_err("test_crc: %s: FAILED:(0x%016llx, expected 0x%016llx)\n",
>> +                       name, crc, expval);
>> +               ret = -EINVAL;
>> +       }
>> +
>> +       return ret;
>> +}
>> +
>> +/* Add your crc test cases here */
>> +static int test_crc64(struct crc_test_record *rec)
>> +{
>> +       u64 crc;
>> +
>> +       crc = crc64(rec->data, sizeof(rec->data));
>> +       return chk_and_msg(rec->name, crc, rec->expval);
>> +}
>> +
>> +static int test_crc64_bch(struct crc_test_record *rec)
>> +{
>> +       u64 crc;
>> +
>> +       crc = crc64_bch(rec->data, sizeof(rec->data));
>> +       return chk_and_msg(rec->name, crc, rec->expval);
>> +}
>> +
>> +static int test_crc64_update(struct crc_test_record *rec)
>> +{
>> +       u64 crc = rec->initval;
>> +
>> +       crc = crc64_update(crc, rec->data, sizeof(rec->data));
>> +       return 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",
>> +         .data         = { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
>> +                           0xC711223CFA3E5BB5, 0x493366450E42ECDF },
>> +         .initval      = 0,
>> +         .expval       = 0xe2b9911e7b997201,
>> +         .handler      = test_crc64,
>> +       },
>> +       { .name         = "crc64_bch",
>> +         .data         = { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
>> +                           0xC711223CFA3E5BB5, 0x493366450E42ECDF },
>> +         .initval      = 0,
>> +         .expval       = 0xd2753a20fd862892,
>> +         .handler      = test_crc64_bch,
>> +       },
>> +       { .name         = "crc64_update",
>> +         .data         = { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
>> +                           0xC711223CFA3E5BB5, 0x493366450E42ECDF },
>> +         .initval      = 0x61C8864680B583EB,
>> +         .expval       = 0xb2c863673f4292bf,
>> +         .handler      = test_crc64_update,
>> +       },
>> +       {}
>> +};
>> +
>> +static int __init test_crc_init(void)
>> +{
>> +       int i;
>> +       int v, err = 0;
>> +
>> +       pr_info("Kernel CRC consitency testing:\n");
>> +       for (i = 0; test_data[i].name; i++) {
>> +               v = test_data[i].handler(&test_data[i]);
>> +               if (v < 0)
>> +                       err++;
>> +       }
>> +
>> +       if (err == 0)
>> +               pr_info("test_crc: all %d tests passed\n", i);
> 
> Similar to previous comment: we should not report the number of passed
> tests, since adding a test would invalidate previous golden output.
> Also, consider the situation where some tests are conditionally
> executed depending on kconfig.

Sure, I fix this in v4 series. Thanks.

Coly Li

[snipped]