From: David Miller <davem@davemloft.net>
To: sandeen@sandeen.net
Cc: matorola@gmail.com, sparclinux@vger.kernel.org,
linux-xfs@vger.kernel.org
Subject: Re: [sparc64] crc32c misbehave
Date: Thu, 01 Jun 2017 17:44:19 -0400 (EDT) [thread overview]
Message-ID: <20170601.174419.2151404855471358626.davem@davemloft.net> (raw)
In-Reply-To: <20170531.124916.1406665885250072302.davem@davemloft.net>
From: David Miller <davem@davemloft.net>
Date: Wed, 31 May 2017 12:49:16 -0400 (EDT)
> From: Eric Sandeen <sandeen@sandeen.net>
> Date: Wed, 31 May 2017 11:31:10 -0500
>
>> On 5/31/17 11:19 AM, Eric Sandeen wrote:
>>> On 5/31/17 10:53 AM, David Miller wrote:
>>>> From: Anatoly Pugachev <matorola@gmail.com>
>>>> Date: Wed, 31 May 2017 14:56:52 +0300
>>>>
>>>>> While debugging occasional crc32c checksum errors with xfs disk reads on
>>>>> sparc64 (T5 [sun4v] 3.6 GHz CPU ldom, debian unstable/sid), Eric have found
>>>>> that crc32c sometimes returns wrong checksum for data. Eric made a simple
>>>>> test kernel module (included), which produce the following results on my
>>>>> sparc64 machines:
>>>
>>> cc: linux-xfs, because this problem cropped up on xfs/sparc.
>>
>> FWIW, the testcase (module which does
>>
>> crc = crc32c(CRC_SEED, data, 512);
>>
>> 1 million times in a loop on the same data, and printk's if
>> the result ever changes) does not fail on x86_64 or ARM
>> (well, not after a gcc bug was fixed on ARM ...)
>
> Is the machine doing things that would cause crc32c() operations in
> interrupts (SCTP protocol traffic) or on other cpus?
>
> That's the danger in comparing other machines, the context and what's
> running on them is different.
Ok, I can reproduce this bug on my systems. I'll see if I can figure out
what is going on.
next prev parent reply other threads:[~2017-06-01 21:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CADxRZqzgaL4ew6PVek3WBsdwo6GcT0ORx=7h+6p0V3NAr8qF+w@mail.gmail.com>
[not found] ` <CADxRZqzNTB1n0g1r_2rLsjifHpJ+_x1WPxNOSqEcHbi74jHi5w@mail.gmail.com>
[not found] ` <20170531.115335.213691069712156732.davem@davemloft.net>
2017-05-31 16:19 ` [sparc64] crc32c misbehave Eric Sandeen
2017-05-31 16:31 ` Eric Sandeen
2017-05-31 16:49 ` David Miller
2017-06-01 21:44 ` David Miller [this message]
2017-06-02 1:57 ` David Miller
2017-06-02 2:10 ` Eric Sandeen
2017-06-02 3:33 ` David Miller
2017-06-02 3:34 ` Eric Sandeen
2017-06-06 19:05 ` David Miller
2017-06-06 19:09 ` Eric Sandeen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170601.174419.2151404855471358626.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=linux-xfs@vger.kernel.org \
--cc=matorola@gmail.com \
--cc=sandeen@sandeen.net \
--cc=sparclinux@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).