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From: "Richard W.M. Jones" <rjones@redhat.com>
To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Lucas Meneghel Rodrigues <lmr@redhat.com>,
	Markus Armbruster <armbru@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] tests: set MALLOC_PERTURB_ to expose memory bugs
Date: Sun, 19 May 2013 17:51:24 +0100	[thread overview]
Message-ID: <20130519165124.GB18311@redhat.com> (raw)
In-Reply-To: <20130517100738.GF2342@redhat.com>


On Fri, May 17, 2013 at 11:07:38AM +0100, Daniel P. Berrange wrote:
> On Fri, May 17, 2013 at 11:54:12AM +0200, Markus Armbruster wrote:
> > If you want punishment, why not go for extra punishment?
> > 
> > MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
> 
> That could lead to non-reproducable failures though. I think it is better
> to use a fixed value so that you're more likely to be able to reproduce
> the issue every time you run the tests.

We've tested libguestfs for years with:

random_val="$(awk 'BEGIN{srand(); print 1+int(255*rand())}' < /dev/null)"
export MALLOC_PERTURB_=$random_val

and have never seen a non-reproducable failure caused by this.

It has, however, caught some simple memory failures, although valgrind
is a lot better if you can afford to run it.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW

  parent reply	other threads:[~2013-05-19 16:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-17  8:52 [Qemu-devel] [PATCH] tests: set MALLOC_PERTURB_ to expose memory bugs Stefan Hajnoczi
2013-05-17  9:54 ` Markus Armbruster
2013-05-17 10:07   ` Daniel P. Berrange
2013-05-17 10:58     ` Markus Armbruster
2013-05-17 12:52       ` Lucas Meneghel Rodrigues
2013-05-17 11:16     ` Stefan Hajnoczi
2013-05-17 12:49     ` Lucas Meneghel Rodrigues
2013-05-19 16:51     ` Richard W.M. Jones [this message]
2013-05-17 11:15   ` Stefan Hajnoczi
2013-05-17 12:50     ` Lucas Meneghel Rodrigues

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