From: Andrea Arcangeli <andrea@novell.com>
Reject zero page vm-area request, align size properly and hide the guard page
from the callers like ioremap - this avoids a kernel crash due one more page
being passed to change_page_attr
Signed-off-by: Andrea Arcangeli <andrea@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/vmalloc.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
diff -puN mm/vmalloc.c~fix-iounmap-and-a-pageattr-memleak-x86-and-x86-64 mm/vmalloc.c
--- 25/mm/vmalloc.c~fix-iounmap-and-a-pageattr-memleak-x86-and-x86-64 Thu Feb 17 16:33:02 2005
+++ 25-akpm/mm/vmalloc.c Thu Feb 17 16:33:02 2005
@@ -252,20 +252,22 @@ struct vm_struct *__get_vm_area(unsigned
align = 1ul << bit;
}
addr = ALIGN(start, align);
+ size = PAGE_ALIGN(size);
area = kmalloc(sizeof(*area), GFP_KERNEL);
if (unlikely(!area))
return NULL;
- /*
- * We always allocate a guard page.
- */
- size += PAGE_SIZE;
if (unlikely(!size)) {
kfree (area);
return NULL;
}
+ /*
+ * We always allocate a guard page.
+ */
+ size += PAGE_SIZE;
+
write_lock(&vmlist_lock);
for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) {
if ((unsigned long)tmp->addr < addr) {
@@ -345,6 +347,11 @@ found:
unmap_vm_area(tmp);
*p = tmp->next;
write_unlock(&vmlist_lock);
+
+ /*
+ * Remove the guard page.
+ */
+ tmp->size -= PAGE_SIZE;
return tmp;
}
_