[LTP] [RFC PATCH 1/9] lib: Add support for guarded buffers

[Richard Palethorpe]

Hello,

Cyril Hrubis <chrubis@suse.cz> writes:

> Hi!
>> >> This commit adds a support for guarder buffers. Guarded buffer is a
>> >> buffer allocated so that there is PROT_NONE page immediatelly after the
>> >> end of the buffer i.e. any access after the buffer generates
>> >> SEGFAULT/EFAULT etc.
>> >> 
>> >> The library is hooked into the tst_test structure so that all you need
>> >> is to fill up an NULL terminated array of buffer pointers and sizes to
>> >> get the respective buffers allocated. The library supports allocating
>> >> memory in test runtime as well as well as allocating more complex
>> >> buffers, which currently are iovec vectors.
>> >
>> > Runtime alloc in loop could be an issue, do we need also runtime free?
>> 
>> I think tst_alloc needs a bit more documentation at the least.
>
> I will write an paragraph to test-writing-guidelines.txt about this
> functionality.
>
>> If we have runtime free then we need to figure out which map the
>> address belongs to or what its offset is (if any).
>
> That's easy, we will store the returned pointer to the map structure
> and use it for comparsion...

So that free() is an O(n) operation where n is the number of maps or you
will use a hash map to make it O(1)?

-- 
Thank you,
Richard.