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Re: [Xen-devel] Grant access to more than one dom

On 05/08/2014 04:03 PM, Simon Martin wrote:
Thanks Daniel,

The add_grefs function strings the allocated gntalloc_gref structures onto
two linked lists: the list heads are local, but are only used temporarily.
If the operation is successful, the list_splice_tail calls wire up the
linked lists to permanent structures on the heap; if unsuccessful, they
are used to clean up.

After sending the mail I kind of worked out the what, however the how
still bugs me. The function list_splice_tail does pointer juggling,
not allocation, so as far as I can see you just end up with pointers to
stack variables...

The allocation is done ingref = kzalloc(sizeof(*gref), GFP_KERNEL).  Any
pointers to stack variables are overwritten during the splice.

Daniel De Graaf
National Security Agency

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