Re: [PATCH] xen/setup: add paranoid index check and warning

From: Martin Kelly
Date: Tue Oct 14 2014 - 10:04:30 EST

On 10/14/2014 02:22 AM, David Vrabel wrote:
> On 14/10/14 02:19, Martin Kelly wrote:
>> In a call to set_phys_range_identity, i-1 is used without checking that
>> i is non-zero. Although unlikely, a bug in the code before it could
>> cause the value to be 0, leading to erroneous behavior. This patch adds
>> a check against 0 value and a corresponding warning.
> This can only happen if the toolstack supplies a memory map with zero
> entries. I could see justification for adding a panic at the top of
> this function in this case, but I can't see the usefulness of this warning.

Yes, a panic is probably appropriate. What do you think about the relative merits of panicing in the callers vs. in the sanitize_e820_map function itself (thus to avoid a bunch of similar error checks in the callers)?
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