From: Mikulas Patocka <mpatocka@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>,
linux-bcachefs@vger.kernel.org, dm-devel@redhat.com,
linux-fsdevel@vger.kernel.org
Subject: Re: fuzzing bcachefs with dm-flakey
Date: Tue, 30 May 2023 08:23:57 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.21.2305300815490.13307@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <ZHUVy7jut1Ex1IGJ@casper.infradead.org>
On Mon, 29 May 2023, Matthew Wilcox wrote:
> On Mon, May 29, 2023 at 04:59:40PM -0400, Mikulas Patocka wrote:
> > Hi
> >
> > I improved the dm-flakey device mapper target, so that it can do random
> > corruption of read and write bios - I uploaded it here:
> > https://people.redhat.com/~mpatocka/testcases/bcachefs/dm-flakey.c
> >
> > I set up dm-flakey, so that it corrupts 10% of read bios and 10% of write
> > bios with this command:
> > dmsetup create flakey --table "0 `blockdev --getsize /dev/ram0` flakey /dev/ram0 0 0 1 4 random_write_corrupt 100000000 random_read_corrupt 100000000"
>
> I'm not suggesting that any of the bugs you've found are invalid, but 10%
> seems really high. Is it reasonable to expect any filesystem to cope
> with that level of broken hardware? Can any of our existing ones cope
> with that level of flakiness? I mean, I've got some pretty shoddy USB
> cables, but ...
If you reduce the corruption probability, it will take more iterations to
hit the bugs.
So, for the "edit-compile-test" loop, the probability should be as high as
possible, just to save the developer's time on testing.
Mikulas
next prev parent reply other threads:[~2023-05-30 12:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-29 20:59 fuzzing bcachefs with dm-flakey Mikulas Patocka
2023-05-29 21:14 ` Matthew Wilcox
2023-05-29 23:12 ` Dave Chinner
2023-05-29 23:51 ` Kent Overstreet
2023-05-30 12:23 ` Mikulas Patocka [this message]
2023-05-29 21:43 ` Kent Overstreet
2023-05-30 21:00 ` Mikulas Patocka
2023-05-30 23:29 ` Kent Overstreet
2023-06-09 20:57 ` Mikulas Patocka
2023-06-09 22:17 ` Kent Overstreet
2023-06-02 1:13 ` Darrick J. Wong
2023-06-09 18:56 ` Mikulas Patocka
2023-06-09 19:38 ` Darrick J. Wong
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