From: Larry Woodman <lwoodman@redhat.com>
Subject: [RHEL5.1 patch] make sure do_brk() correctly returns EINVAL for ppc64.  
Date: Mon, 09 Apr 2007 16:58:35 -0400
Bugzilla: 224261
Message-Id: <461AA8FB.4030604@redhat.com>
Changelog: [mm] make do_brk() correctly return EINVAL for ppc64.  


do_brk() doesn't check if the newly allocated address space intersects 
a hugepage region.  This means it could create a normal page VMA which 
extends into a hugepage-only address region on powerpc instead of returning
EINVAL. 

The following upstream patch fixes this problem by making sure addr+len 
doesnt
extend into a hugepage region.  Fixes BZ 224261.






--- linux-2.6.18.noarch/mm/mmap.c.orig
+++ linux-2.6.18.noarch/mm/mmap.c
@@ -1966,7 +1966,8 @@ unsigned long do_brk(unsigned long addr,
 	if (!len)
 		return addr;
 
-	if ((addr + len) > TASK_SIZE || (addr + len) < addr)
+	if (((addr + len) > TASK_SIZE) || ((addr + len) < addr) ||
+			is_hugepage_only_range(mm, addr, len))
 		return -EINVAL;
 
 	flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;