From: "David M. Lloyd" <dmlloyd@flurg.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: "Michael K. Edwards" <medwards.linux@gmail.com>,
Bodo Eggert <7eggert@gmx.de>, Eric Dumazet <dada1@cosmosbay.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: sys_write() racy for multi-threaded append?
Date: Tue, 13 Mar 2007 09:00:31 -0500 [thread overview]
Message-ID: <1173794431.6729.32.camel@localhost> (raw)
In-Reply-To: <20070313022430.57503b08@lxorguk.ukuu.org.uk>
On Tue, 2007-03-13 at 02:24 +0000, Alan Cox wrote:
> > purports to handle short writes but has never been exercised is
> > arguably worse than code that simply bombs on short write. So if I
> > can't shim in an induce-short-writes-randomly-on-purpose mechanism
> > during development, I don't want short writes in production, period.
>
> Easy enough to do and gcov plus dejagnu or similar tools will let you
> coverage analyse the resulting test set and replay it.
You don't even need special tools: just change your code that says:
foo = write(fd, mybuf, mycount);
to say (for example):
foo = write(fd, mybuf, mycount / randomly_either_1_or_2);
Why would this need kernel support? The average developer doesn't
really need to verify that the *kernel* works. They just need to test
their own code paths - and in this case, they can see that foo is less
than mycount (sometimes). The code paths don't care that it was not the
kernel that caused it.
- DML
next prev parent reply other threads:[~2007-03-13 14:02 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <7WzUo-1zl-21@gated-at.bofh.it>
[not found] ` <7WAx2-2pg-21@gated-at.bofh.it>
[not found] ` <7WAGF-2Bx-9@gated-at.bofh.it>
[not found] ` <7WB07-3g5-33@gated-at.bofh.it>
[not found] ` <7WBt7-3SZ-23@gated-at.bofh.it>
2007-03-12 7:53 ` sys_write() racy for multi-threaded append? Bodo Eggert
2007-03-12 16:26 ` Michael K. Edwards
2007-03-12 18:48 ` Bodo Eggert
2007-03-13 0:46 ` Michael K. Edwards
2007-03-13 2:24 ` Alan Cox
2007-03-13 7:25 ` Michael K. Edwards
2007-03-13 7:42 ` David Miller
2007-03-13 16:24 ` Michael K. Edwards
2007-03-13 17:59 ` Michael K. Edwards
2007-03-13 19:09 ` Christoph Hellwig
2007-03-13 23:40 ` Michael K. Edwards
2007-03-14 0:09 ` Michael K. Edwards
2007-03-13 13:15 ` Alan Cox
2007-03-14 20:09 ` Michael K. Edwards
2007-03-16 16:43 ` Frank Ch. Eigler
2007-03-16 17:25 ` Alan Cox
2007-03-13 14:00 ` David M. Lloyd [this message]
2007-03-08 23:08 Michael K. Edwards
2007-03-08 23:43 ` Eric Dumazet
2007-03-08 23:57 ` Michael K. Edwards
2007-03-09 0:15 ` Eric Dumazet
2007-03-09 0:45 ` Michael K. Edwards
2007-03-09 1:34 ` Benjamin LaHaise
2007-03-09 12:19 ` Michael K. Edwards
2007-03-09 13:44 ` Eric Dumazet
2007-03-09 14:10 ` Alan Cox
2007-03-09 14:59 ` Benjamin LaHaise
2007-03-10 6:43 ` Michael K. Edwards
2007-03-09 5:53 ` Eric Dumazet
2007-03-09 11:52 ` Michael K. Edwards
2007-03-09 0:43 ` Alan Cox
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