Re: [patch] infiniband: uverbs: limit the number of entries

Nicolas Palix
2010-10-08T07:59:47Z

Hi,

On Thu, Oct 7, 2010 at 6:59 PM, Dan Carpenter <error27@gmail.com> wrote:
> On Thu, Oct 07, 2010 at 10:16:49AM -0600, Jason Gunthorpe wrote:
>> On Thu, Oct 07, 2010 at 09:16:10AM +0200, Dan Carpenter wrote:
>> > If we don't limit cmd.ne then the multiplications can overflow.  This
>> > will allocate a small amount of RAM successfully for the "resp" and
>> > "wc" buffers.  The heap will get corrupted when we call ib_poll_cq().
>>
>> I think you could cap the number of returned entries to
>> UVERBS_MAX_NUM_ENTRIES rather than return EINVAL. That might be more
>> compatible with user space..
>>
>
> Good idea.  I don't actually have this hardware, so I can't test it, but
> that definitely sounds reasonable.
>
> If we did that then UVERBS_MAX_NUM_ENTRIES could be lower than 1000.
> What is a reasonable number?

You can also use kcalloc to allocate wc.

>
> regards,
> dan carpenter
>
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--
Nicolas Palix
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