[Crash-utility] handling missing kdump pages in diskdump format

I've been experimenting with the makedumpfile utility for kdump on ia64. One of my experiments was to verify that a page that should have been missing indeed was missing. I used crash 4.0-3.8 to look for a user page that should have been omitted from the dump. crash> x/xg 0xe0000040fc00c000 0xe0000040fc00c000: 0x0000000000000000 On a full dump from makedumpfile as well as on a straight copy of vmcore, crash reports this: crash> x/xg 0xe0000040fc00c000 0xe0000040fc00c000: 0x00010102464c457f The dumpfiles created by makedumpfile appear to crash as diskdump files, and crash appears to excuse missing pages and report 0x0 contents here: diskdump.c:read_diskdump, line 454: if (!page_is_dumpable(pfn)) { memset(bufptr, 0, cnt); return cnt; Shouldn't there be some indication that a requested page is missing as opposed to being legitimately full of zeros? Bob Montgomery