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Subject: Re: [PATCH 4/4] lib/test_crc: Add test cases for crc calculation
To:     Randy Dunlap <rdunlap@infradead.org>, linux-kernel@vger.kernel.org
Cc:     linux-bcache@vger.kernel.org, linux-block@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Luis R . Rodriguez" <mcgrof@suse.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Kate Stewart <kstewart@linuxfoundation.org>
References: <20180716165507.23100-1-colyli@suse.de>
 <20180716165507.23100-5-colyli@suse.de>
 <02a39b74-918b-a9ab-5023-99c11a8ac832@infradead.org>
From:   Coly Li <colyli@suse.de>
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Message-ID: <d29ac200-afed-6cb3-063a-ba2b00251416@suse.de>
Date:   Tue, 17 Jul 2018 11:37:44 +0800
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On 2018/7/17 2:05 AM, Randy Dunlap wrote:
> On 07/16/2018 09:55 AM, 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_le: PASSED (0x4e6b1ff972fa8c55, expval 0x4e6b1ff972fa8c55)
>> test_crc: crc64_le_bch: PASSED (0x0e4f1391d7a4a62e, expval 0x0e4f1391d7a4a62e)
>> test_crc: crc64_le_update: FAILED (0x03d4d0d85685d9a1, expval 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.
>>

Hi Randy,

>> lib/test_crc.c can is a testing frame work for all crc consistency
> 
>             drop ^^^ "can"
> 

All the following issues are fixed in v2 series, thank you for the review.

> Well, we already have (from lib/Makefile):
> obj-$(CONFIG_CRC32_SELFTEST)	+= crc32test.o
> 
> so lib/test_crc.c isn't exactly "for all crc".
> 

My plan is to add extra consistency test cases for crc32/crc32c for
consistency testing. Consistency testing case is much simpler than the
code in crc32test.c, the results of test_crc.c are in unified format so
0day testing can handle them in a simple way.

I agree with you that 'for all crc' is inaccurate before the
crc32/crc32c test cases added into test_crc. So in v2 series, it will be
modified to 'for many crc consistency testings'.

Thanks.

Coly Li

> 
>> testings. For now, there are only test caes for 3 crc routines,
>> - crc64_le()
>> - crc64_le_bch()
>> - crc64_le_update()
>>
>> Signed-off-by: Coly Li <colyli@suse.de>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Luis R. Rodriguez <mcgrof@suse.com>
>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Kate Stewart <kstewart@linuxfoundation.org>
>> ---
>>  lib/Kconfig.debug |  11 ++++
>>  lib/Makefile      |   1 +
>>  lib/test_crc.c    | 136 ++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 148 insertions(+)
>>  create mode 100644 lib/test_crc.c
> 
> 
>> diff --git a/lib/test_crc.c b/lib/test_crc.c
>> new file mode 100644
>> index 000000000000..3a9442252de5
>> --- /dev/null
>> +++ b/lib/test_crc.c
>> @@ -0,0 +1,136 @@
>> +// 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
> 
>                    CRC
> 
>> + * 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_le()
>> + * - crc64_le_bch()
>> + * - crc64_le_update()
>> + *
>> + */
>> +
>> +#include <linux/init.h>
>> +#include <linux/list.h>
>> +#include <linux/module.h>
>> +#include <linux/printk.h>
>> +#include <linux/fs.h>
>> +#include <linux/miscdevice.h>
>> +#include <linux/slab.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/async.h>
>> +#include <linux/delay.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/crc64.h>
>> +
>> +struct crc_test_record {
>> +
>> +	char	*name;
>> +	__le64	data[4];
>> +	__le64	initval;
>> +	__le64	expval;
>> +	int	(*handler)(struct crc_test_record *rec);
>> +};
>> +
>> +static int chk_and_msg(const char *name, __le64 crc, __le64 expval)
>> +{
>> +	int ret = 0;
>> +
>> +	if (crc == expval) {
>> +		pr_info("test_crc: %s: PASSED:(0x%016llx, expval 0x%016llx)",
>> +			name, crc, expval);
>> +	} else {
>> +		pr_err("test_crc: %s: FAILED:(0x%016llx, expval 0x%016llx)",
>> +			name, crc, expval);
> 
> For both pr_err() lines, please print "expected" instead of "expval".
> 
>> +		ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +/* Add your crc test caese here */
> 
>                CRC test cases
> 
>> +static int test_crc64_le(struct crc_test_record *rec)
>> +{
>> +	__le64 crc;
>> +
>> +	crc = crc64_le(rec->data, sizeof(rec->data));
>> +	return chk_and_msg(rec->name, crc, rec->expval);
>> +
>> +}
>> +
>> +static int test_crc64_le_bch(struct crc_test_record *rec)
>> +{
>> +	__le64 crc;
>> +
>> +	crc = crc64_le_bch(rec->data, sizeof(rec->data));
>> +	return chk_and_msg(rec->name, crc, rec->expval);
>> +}
>> +
>> +static int test_crc64_le_update(struct crc_test_record *rec)
>> +{
>> +	__le64 crc = rec->initval;
>> +
>> +	crc = crc64_le_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_le",
>> +	  .data		= { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
>> +			    0xC711223CFA3E5BB5, 0x493366450E42ECDF },
>> +	  .initval	= 0,
>> +	  .expval	= 0xe2b9911e7b997201,
>> +	  .handler	= test_crc64_le,
>> +	},
>> +	{ .name		= "crc64_le_bch",
>> +	  .data		= { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
>> +			    0xC711223CFA3E5BB5, 0x493366450E42ECDF },
>> +	  .initval	= 0,
>> +	  .expval	= 0xd2753a20fd862892,
>> +	  .handler	= test_crc64_le_bch,
>> +	},
>> +	{ .name		= "crc64_le_update",
>> +	  .data		= { 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
>> +			    0xC711223CFA3E5BB5, 0x493366450E42ECDF },
>> +	  .initval	= 0x61C8864680B583EB,
>> +	  .expval	= 0xb2c863673f4292bf,
>> +	  .handler	= test_crc64_le_update,
>> +	},
>> +	{ .name = NULL, }
>> +};
>> +
>> +
>> +static int __init test_crc_init(void)
>> +{
>> +	int i;
>> +	int v, ret = 0;
>> +
>> +	pr_info("Kernel crc consitency testing:");
> 
> 	                CRC consistency
> 
>> +	for (i = 0; test_data[i].name; i++) {
>> +		v = test_data[i].handler(&test_data[i]);
>> +		if (v < 0 && ret == 0)
>> +			ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +late_initcall(test_crc_init);
>> +
>> +static void __exit test_crc_exit(void) { }
>> +module_exit(test_crc_exit);
>> +
>> +MODULE_DESCRIPTION("CRC consistency testing driver");
>> +MODULE_AUTHOR("Coly Li <colyli@suse.de>");
>> +MODULE_LICENSE("GPL");
>>
> 
> 
> thanks,
>