linux-kernel - Re: [PATCH v2 3/3] lib/test_crc: Add test cases for crc calculation

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Date:   Tue, 17 Jul 2018 10:32:45 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Coly Li <colyli@...e.de>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-bcache@...r.kernel.org, linux-block@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kate Stewart <kstewart@...uxfoundation.org>
Subject: Re: [PATCH v2 3/3] lib/test_crc: Add test cases for crc calculation

On Tue, Jul 17, 2018 at 9:57 AM, Coly Li <colyli@...e.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_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.
>
> 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_le()
> - crc64_le_bch()
> - crc64_le_update()

> +config TEST_CRC
> +       tristate "CRC calculation test driver"
> +       depends on CRC64

> +       default n

Please, remove it.
You Cc'ed the guy who did this:
http://git.infradead.org/linux-platform-drivers-x86.git/commit/0192f17529fa3f8d78ca0181a2b2aaa7cbb0784d

> +       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.

> +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, expected 0x%016llx)",
> +                       name, crc, expval);
> +       } else {
> +               pr_err("test_crc: %s: FAILED:(0x%016llx, expected 0x%016llx)",
> +                       name, crc, expval);
> +               ret = -EINVAL;
> +       }
> +
> +       return ret;
> +}

> +
> +

One of the blank lines is redundant.

> +static int __init test_crc_init(void)
> +{
> +       int i;
> +       int v, ret = 0;
> +
> +       pr_info("Kernel CRC consitency testing:");
> +       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;
> +}

Didn't notice anything about statistics.

See, for example,
https://elixir.bootlin.com/linux/v4.18-rc5/source/lib/test_printf.c#L536

-- 
With Best Regards,
Andy Shevchenko