Two patches from NetBSD:

- extent_alloc_subregion shouldn't allocate a region pasts the end of subregion.
- extent_alloc_subregion1(): when a candidate region doesn't fit after being
rounded up to respect boundary limits, adjust newstart and last before
skiping to the next region. Otherwise we may check the same candidate
region against the start of the next region, no the one immediatly following
the hole, leading to corrupted map.

1 files changed, 25 insertions, 16 deletions

diff --git a/sys/kern/subr_extent.c b/sys/kern/subr_extent.c
index 3ac43139310..03c8447f202 100644
--- a/sys/kern/subr_extent.c
+++ b/sys/kern/subr_extent.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_extent.c,v 1.20 2002/03/14 01:27:04 millert Exp $	*/
+/*	$OpenBSD: subr_extent.c,v 1.21 2002/03/21 16:24:16 jason Exp $	*/
 /*	$NetBSD: subr_extent.c,v 1.7 1996/11/21 18:46:34 cgd Exp $	*/
 
 /*-
@@ -183,8 +183,8 @@ extent_create(name, start, end, mtype, storage, storagesize, flags)
 		panic("extent_create: end < start");
 	}
 	if (fixed_extent && (storagesize < sizeof(struct extent_fixed)))
-		panic("extent_create: fixed extent, bad storagesize 0x%x",
-		    storagesize);
+		panic("extent_create: fixed extent, bad storagesize 0x%lx",
+		    (u_long)storagesize);
 	if (fixed_extent == 0 && (storagesize != 0 || storage != NULL))
 		panic("extent_create: storage provided for non-fixed");
 #endif
@@ -533,7 +533,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 	u_long *result;
 {
 	struct extent_region *rp, *myrp, *last, *bestlast;
-	u_long newstart, newend, beststart, bestovh, ovh;
+	u_long newstart, newend, exend, beststart, bestovh, ovh;
 	u_long dontcross;
 	int error;
 
@@ -605,6 +605,12 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 	bestlast = NULL;
 
 	/*
+	 * Keep track of end of free region.  This is either the end of extent
+	 * or the start of a region past the subend.
+	 */
+	exend = ex->ex_end;
+
+	/*
 	 * For N allocated regions, we must make (N + 1)
 	 * checks for unallocated space.  The first chunk we
 	 * check is the area from the beginning of the subregion
@@ -645,6 +651,15 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 
 	for (; rp != NULL; rp = rp->er_link.le_next) {
 		/*
+		 * If the region pasts the subend, bail out and see
+		 * if we fit against the subend.
+		 */
+		if (rp->er_start >= subend) {
+			exend = rp->er_start;
+			break;
+		}
+
+		/*
 		 * Check the chunk before "rp".  Note that our
 		 * comparison is safe from overflow conditions.
 		 */
@@ -661,7 +676,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 				 * Calculate the next boundary after the start
 				 * of this region.
 				 */
-				dontcross = EXTENT_ALIGN(newstart+1, boundary,
+				dontcross = EXTENT_ALIGN(newstart+1, boundary, 
 				    (flags & EX_BOUNDZERO) ? 0 : ex->ex_start)
 				    - 1;
 
@@ -684,7 +699,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 					newend = newstart + (size - 1);
 					dontcross += boundary;
 					if (!LE_OV(newstart, size, rp->er_start))
-						continue;
+						goto skip;
 				}
 
 				/*
@@ -719,6 +734,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 			}
 		}
 
+skip:
 		/*
 		 * Skip past the current region and check again.
 		 */
@@ -731,14 +747,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 			 */
 			goto fail;
 		}
-
-		/*
-		 * Check that the current region don't run past the
-		 * end of the subregion.
-		 */
-		if (!LE_OV(newstart, (size - 1), subend))
-			goto fail;
-
+		
 		last = rp;
 	}
 
@@ -762,7 +771,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 			 * Calculate the next boundary after the start
 			 * of this region.
 			 */
-			dontcross = EXTENT_ALIGN(newstart+1, boundary,
+			dontcross = EXTENT_ALIGN(newstart+1, boundary, 
 			    (flags & EX_BOUNDZERO) ? 0 : ex->ex_start)
 			    - 1;
 
@@ -805,7 +814,7 @@ extent_alloc_subregion(ex, substart, subend, size, alignment, skew, boundary,
 		 * fit, or we're taking the first fit, insert
 		 * ourselves into the region list.
 		 */
-		ovh = ex->ex_end - newstart - (size - 1);
+		ovh = exend - newstart - (size - 1);
 		if ((flags & EX_FAST) || (ovh == 0))
 			goto found;