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Date: Wed, 1 Feb 2017 17:39:21 +0100
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Olaf Weber <olaf@sgi.com>
Cc: James Simmons <jsimmons@infradead.org>,
        Dan Carpenter <dan.carpenter@oracle.com>, devel@driverdev.osuosl.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Oleg Drokin <oleg.drokin@intel.com>,
        Amir Shehata <amir.shehata@intel.com>,
        Lustre Development List <lustre-devel@lists.lustre.org>
Subject: Re: [lustre-devel] [PATCH 60/60] staging: lustre: libcfs: fix
 minimum size check for libcfs ioctl
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On Wed, Feb 01, 2017 at 02:32:13PM +0100, Olaf Weber wrote:
> On 31-01-17 03:25, James Simmons wrote:
> 
> [...]
> 
> > > Also I'm uncomfortable with:
> > > 
> > > 	data = container_of(hdr, struct libcfs_ioctl_data, ioc_hdr);
> > > 
> > > If hdr isn't the first member of the struct then the code is broken but
> > > container_of() implies that that isn't a hard requirement.  It should
> > > just be:
> > > 
> > > 	data = (struct libcfs_ioctl_data *)hdr;
> > 
> > Don't know if hdr being first is a hard requirment. Doug, Amir do you know
> > if it is an requirement?
> 
> It's a requirement.

That's horrid.  Use container_of to be "safe" here please...