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From: Dave Chinner <david@fromorbit.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: bugzilla-daemon@bugzilla.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [Bug 208827] [fio io_uring] io_uring write data crc32c verify failed
Date: Tue, 11 Aug 2020 17:05:05 +1000	[thread overview]
Message-ID: <20200811070505.GO2114@dread.disaster.area> (raw)
In-Reply-To: <d7c9ea39-136d-bc1b-7282-097a784e336b@kernel.dk>

On Mon, Aug 10, 2020 at 08:19:57PM -0600, Jens Axboe wrote:
> On 8/10/20 8:00 PM, Dave Chinner wrote:
> > On Mon, Aug 10, 2020 at 07:08:59PM +1000, Dave Chinner wrote:
> >> On Mon, Aug 10, 2020 at 05:08:07PM +1000, Dave Chinner wrote:
> >>> [cc Jens]
> >>>
> >>> [Jens, data corruption w/ io_uring and simple fio reproducer. see
> >>> the bz link below.]
> > 
> > Looks like a io_uring/fio bugs at this point, Jens. All your go fast
> > bits turns the buffered read into a short read, and neither fio nor
> > io_uring async buffered read path handle short reads. Details below.
> 
> It's a fio issue. The io_uring engine uses a different path for short
> IO completions, and that's being ignored by the backend... Hence the
> IO just gets completed and not retried for this case, and that'll then
> trigger verification as if it did complete. I'm fixing it up.

I just updated fio to:

cb7d7abb (HEAD -> master, origin/master, origin/HEAD) io_u: set io_u->verify_offset in fill_io_u()

The workload still reports corruption almost instantly. Only this
time, the trace is not reporting a short read.

File is patterned with:

verify_pattern=0x33333333%o-16

Offset of "bad" data is 0x1240000.

Expected:

00000000:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000010:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000020:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000030:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000040:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000050:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000060:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000070:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
00000080:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff 3333............
.....
0000ffd0:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff  3333............
0000ffe0:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff  3333............
0000fff0:  33 33 33 33 00 10 24 01 00 00 00 00 f0 ff ff ff  3333............


Received:

00000000:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000010:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000020:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000030:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000040:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000050:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000060:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000070:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
00000080:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff 3333............
.....
0000ffd0:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff  3333............
0000ffe0:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff  3333............
0000fff0:  33 33 33 33 00 00 24 01 00 00 00 00 f0 ff ff ff  3333............


Looks like the data in the expected buffer is wrong - the data
pattern in the received buffer is correct according the defined
pattern.

Error is 100% reproducable from the same test case. Same bad byte in
the expected buffer dump every single time.

-Dave.
-- 
Dave Chinner
david@fromorbit.com

  parent reply	other threads:[~2020-08-11  7:05 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-06  4:57 [Bug 208827] New: [fio io_uring] io_uring write data crc32c verify failed bugzilla-daemon
2020-08-07  2:42 ` Dave Chinner
2020-08-07  3:12 ` [Bug 208827] " bugzilla-daemon
2020-08-10  0:09   ` Dave Chinner
2020-08-10  3:56     ` Dave Chinner
2020-08-10  7:08       ` Dave Chinner
2020-08-10  9:08         ` Dave Chinner
2020-08-11  1:15           ` Jens Axboe
2020-08-11  1:50             ` Jens Axboe
2020-08-11  2:01               ` Jens Axboe
2020-08-11  3:01                 ` Jens Axboe
2020-08-11 20:56                 ` Jeff Moyer
2020-08-11 22:09                   ` Dave Chinner
2020-08-12 15:13                     ` Jens Axboe
2020-08-12 15:24                       ` Jeff Moyer
2020-08-12 15:26                         ` Jens Axboe
2020-08-11  2:00           ` Dave Chinner
2020-08-11  2:19             ` Jens Axboe
2020-08-11  5:53               ` Dave Chinner
2020-08-11  7:05               ` Dave Chinner [this message]
2020-08-11 13:10                 ` Jens Axboe
2020-08-11 21:59                   ` Dave Chinner
2020-08-11 23:00                     ` Dave Chinner
2020-08-12 15:19                       ` Jens Axboe
2020-08-11  1:07         ` Jens Axboe
2020-08-10  0:09 ` bugzilla-daemon
2020-08-10  3:56 ` bugzilla-daemon
2020-08-10  7:08 ` bugzilla-daemon
2020-08-10  9:09 ` bugzilla-daemon
2020-08-11  1:07 ` bugzilla-daemon
2020-08-11  1:15 ` bugzilla-daemon
2020-08-11  1:50 ` bugzilla-daemon
2020-08-11  2:00 ` bugzilla-daemon
2020-08-11  2:01 ` bugzilla-daemon
2020-08-11  2:20 ` bugzilla-daemon
2020-08-11  3:01 ` bugzilla-daemon
2020-08-11  5:53 ` bugzilla-daemon
2020-08-11  7:05 ` bugzilla-daemon
2020-08-11 13:10 ` bugzilla-daemon
2020-08-11 16:16 ` bugzilla-daemon
2020-08-11 20:56 ` bugzilla-daemon
2020-08-11 21:59 ` bugzilla-daemon
2020-08-11 22:09 ` bugzilla-daemon
2020-08-11 23:00 ` bugzilla-daemon
2020-08-12  3:15 ` bugzilla-daemon
2020-08-12 15:14 ` bugzilla-daemon
2020-08-12 15:19 ` bugzilla-daemon
2020-08-12 15:24 ` bugzilla-daemon
2020-08-12 15:26 ` bugzilla-daemon

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