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Add checks to vm_map_findspace() to test for address wrap. The conditions

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where this could occur are very rare, but possible.

Submitted by: Mark W. Krentel
MFC after: 2 weeks
This commit is contained in:
Alan Cox 2005-01-18 19:50:09 +00:00
parent c4dc6d1307
commit 986b43f845
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=140439
1 changed files with 8 additions and 4 deletions
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12
sys/vm/vm_map.c
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@ -1009,10 +1009,13 @@ vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length,
vm_map_entry_t entry;
vm_offset_t end, st;
/* Request must fit within min/max VM address. */
/*
* Request must fit within min/max VM address and must avoid
* address wrap.
*/
if (start < map->min_offset)
start = map->min_offset;
if (start + length > map->max_offset)
if (start + length > map->max_offset || start + length < start)
return (1);
/* Empty tree means wide open address space. */
@ -1033,10 +1036,11 @@ vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length,
/*
* Root is the last node that might begin its gap before
* start.
* start, and this is the last comparison where address
* wrap might be a problem.
*/
st = (start > map->root->end) ? start : map->root->end;
if (st + length <= map->root->end + map->root->adj_free) {
if (length <= map->root->end + map->root->adj_free - st) {
*addr = st;
goto found;
}