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Message-ID: <6e0cfd1d0608301040kf347dc8w6088a1fc8cd8b2b1@mail.gmail.com>
Date: Wed, 30 Aug 2006 19:40:19 +0200
From: "Martin Schwidefsky" <schwidefsky@googlemail.com>
To: "David Wagner" <daw-usenet@taverner.cs.berkeley.edu>
Subject: Re: [S390] cio: kernel stack overflow.
Cc: linux-kernel@vger.kernel.org
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	 <ed4gno$d29$1@taverner.cs.berkeley.edu>
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On 8/30/06, David Wagner <daw@cs.berkeley.edu> wrote:
> Have you checked that in all cases all fields of the struct have
> been overwritten?  For instance, look at this:
>
> Martin Schwidefsky  wrote:
> >-      chp->dev = (struct device) {
> >-              .parent  = &css[0]->device,
> >-              .release = chp_release,
> >-      };
> >+      chp->dev.parent = &css[0]->device;
> >+      chp->dev.release = chp_release;
>
> Doesn't this leave chp->dev.bus still holding whatever old value it
> had laying around before?  Unless I'm missing something, it looks to
> me like this diff causes a change in the semantics of the code.
>
> Perhaps it would be better to memset() the entire struct (chp->dev, in
> this case) to zero, before assigning to individual fields, so there is
> no possibility of old remnant data still being left laying around?

The structure is allocated with kzalloc().

-- 
blue skies,
  Martin
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