Re: [PATCH 1/3] uprobes: fix the usage of install_special_mapping()

[Andy Lutomirski]

On Thu, Jul 9, 2015 at 3:02 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> On 07/09, Andy Lutomirski wrote:
>>
>> On Thu, Jul 9, 2015 at 2:44 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>> > install_special_mapping(pages) expects that "pages" is the zero-
>> > terminated array while xol_add_vma() passes &area->page, this means
>> > that special_mapping_fault() can wrongly use the next member in
>> > xol_area (vaddr) as "struct page *".
>> >
>> > Fortunately, this area is not expandable so pgoff != 0 isn't possible
>> > (modulo bugs in special_mapping_vmops), but still this does not look
>> > good.
>> >
>>
>> I fell for that awhile back, too, causing a bizarre HPET bug.
>
> I guess you mean no_pages[] = {NULL} in map_vdso() ?

Yes.

--Andy
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