PATCH: bug in locate_hole()

[Matthew Fleming]

In upgrading to kexec-tools 2.0.5 I first got the error "Overlapping
memory segments at 0xbeff000"

Adding some debugging I found locate_hole was returning incorrect
values.  The below is from the debug I added:

XXXMDF: look for hole size 100000, cur range [52b3000, bffffff] size 6d4cfff
XXXMDF: look for hole memsz=100000, found beff000

Hmm, if we wanted 0x100000 bytes ending at 0xbffffff, that should be
0xbf00000, not 0xbef000.  Continuing to the second invocation:

XXXMDF: look for hole size 1000, cur range [52b3000, befefff] size 6c4bfff
XXXMDF: look for hole size 1000, cur range [bfff000, bffffff] size fff
XXXMDF: look for hole memsz=1000, found bffe000

Now we die with overlapping ranges, since the 0x100000 bytes at
0xbeff000 overlaps 0x1000 bytes at 0xbffe000.

The attached patch fixes the off-by-one that causes the later overlap.

Thanks,
matthew
-------------- next part --------------
--- kexec.c.orig	2014-03-03 16:08:53.289844106 -0800
+++ kexec.c	2014-03-03 16:09:04.960844107 -0800
@@ -272,17 +272,17 @@ unsigned long locate_hole(struct kexec_i
 		}
 		/* Is there enough space left so we can use it? */
 		size = end - start;
 		if (!hole_size || size >= hole_size - 1) {
 			if (hole_end > 0) {
 				hole_base = start;
 				break;
 			} else {
-				hole_base = _ALIGN_DOWN(end - hole_size,
+				hole_base = _ALIGN_DOWN(end - hole_size + 1,
 					hole_align);
 			}
 		}
 	}
 	free(mem_range);
 	if (hole_base == ULONG_MAX) {
 		fprintf(stderr, "Could not find a free area of memory of "
 			"0x%lx bytes...\n", hole_size);