On Tue, Oct 14, 2014 at 9:09 AM, David Vrabel <david.vra...@citrix.com> wrote: > On 14/10/14 15:04, Martin Kelly wrote: >> 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)? > > For Xen, it should panic immediately after getting the memory map. > > You will note that there is fallback code for the case when no memory > map is provided. But I do not think this should be used in the case > where the toolstack provided an empty memory map. > > David
Sounds like the flow should be as follows: 1) Ask Xen for the memory map. 2) If no memory map is provided, use fallback code. 3) If the memory map has 0 entries, panic. I will revise the patch to do that. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
