POWER: Unexpected fault when writing to brk-allocated memory

[Florian Weimer]

On 11/06/2017 07:18 AM, Aneesh Kumar K.V wrote:
> We should not return that address, unless we requested with a hint value
> of > 128TB. IIRC we discussed this early during the mmap interface
> change and said, we will return an address > 128T only if the hint
> address is above 128TB (not hint addr + length). I am not sure why
> we are finding us returning and address > 128TB with paca limit set to
> 128TB?

See the memory maps I posted.  I think it was not anticipated that the 
heap could be near the 128 TiB limit because it is placed next to the 
initially mapped object.

I think this could become worse once we have static PIE support because 
static PIE binaries likely have the same memory layout.  (Ordinary PIE 
does not.)

Thanks,
Florian