Re: [PATCH 10/28] i386: map enough initial memory to create lowmem mappings

Chuck Ebbert
2007-04-19T21:23:08Z

H. Peter Anvin wrote:
> Andi Kleen wrote:
>> On Thursday 19 April 2007 22:55:50 H. Peter Anvin wrote:
>>> Andi Kleen wrote:
>>>>> Is some version of this going in for 2.6.21, or is it not a real
>>>>> problem?
>>>> When it's only seen with Xen it's not a real problem right now.
>>> It's not just seen only with Xen, though. It will affect all kernels
>>> in a particular range of sizes, and we have ordinary kernels covering
>>> that range (in fact, Xen hardly affects size in that way.)
>>
>> Then we would have seen reports surely?
>
> The critical size window is relatively small, though. The size of the
> uncompressed kernel mod 4 MB must be above 3.75 MB or so. If you have
> less than 1 GB RAM, the window is even smaller. This is strictly
> configuration-dependent, and has nothing to do with Xen. It just so
> happened that the first people to detect and diagnose it (as opposed to
> just "it doesn't boot") were Xen people.

I never saw a description of the symptoms of encountering this bug.
Does it just hang, or what?