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fix checks for expand-in-place mremap

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Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2009-11-24 08:25:18 -05:00
parent 1a0ef85f84
commit f106af4e90
1 changed files with 11 additions and 2 deletions
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13
mm/mremap.c
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@ -27,6 +27,10 @@
#include "internal.h"
#ifndef arch_mmap_check
#define arch_mmap_check(addr, len, flags) (0)
#endif
static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
@ -368,12 +372,17 @@ static unsigned long mremap_to(unsigned long addr,
static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
{
unsigned long end = vma->vm_end + delta;
unsigned long max_addr = TASK_SIZE;
if (vma->vm_next)
max_addr = vma->vm_next->vm_start;
if (max_addr - vma->vm_end < delta)
if (max_addr < end || end < vma->vm_end)
return 0;
if (arch_mmap_check(vma->vm_start, end - vma->vm_start, MAP_FIXED))
return 0;
if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
0, MAP_FIXED) & ~PAGE_MASK)
return 0;
/* we need to do arch-specific checks here */
return 1;
}