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Date: Sun, 8 Oct 2017 15:51:37 -0300
From: Ernesto =?utf-8?Q?A=2E_Fern=C3=A1ndez?=
        <ernesto.mnd.fernandez@gmail.com>
To: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Sergei Antonov <saproj@gmail.com>,
        Vyacheslav Dubeyko <slava@dubeyko.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        Ernesto =?utf-8?Q?A=2E_Fern=C3=A1ndez?=
        <ernesto.mnd.fernandez@gmail.com>, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] hfsplus: fix segfault when deleting all attrs of a file
Message-ID: <20171008185136.GA1272@debian.home>
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On Sat, Oct 07, 2017 at 04:25:22AM +0000, Hin-Tak Leung wrote:
> 
> --------------------------------------------
> On Sat, 7/10/17, Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> wrote:
>  
> > A segmentation fault can be triggered by setting many xattrs
> > to a file
> > and then deleting it. The number must be high enough for
> > more than one
> > b-tree node to be needed for storage.
> 
> Sounds like it is easily/reliably reproducible - do you have an estimate/recipe of how many xattrs minimum to trigger this problem, to test and verify this fix?

I did not give a number because it depends on the size of the xattrs, and I
imagine the bnode size as well, though I only tested it with the default
mkfs options. Maybe I should have shared the script I used instead:

touch test.file
i=1
while [ $i -le 250 ]; do
  setfattr -n user.$i test.file
  ((++i))
done
rm test.file

Of course, if you set a value to the xattrs you will need fewer.

> Thanks a lot for the work!

And thank you for your attention.

> Hin-Tak
> 
>  

Ernest