commit
9d8cebd4bcd7 ("mm: fix mbind vma merge problem") didn't really
fix the mbind vma merge problem due to wrong pgoff value passing to
vma_merge(), which made vma_merge() always return NULL.
Before the patch applied, we are getting a result like:
addr = 0x7fa58f00c000
[snip]
7fa58f00c000-
7fa58f00d000 rw-p
00000000 00:00 0
7fa58f00d000-
7fa58f00e000 rw-p
00000000 00:00 0
7fa58f00e000-
7fa58f00f000 rw-p
00000000 00:00 0
here
7fa58f00c000->
7fa58f00f000 we get 3 VMAs which are expected to be
merged described as described in commit 9d8cebd.
Re-testing the patched kernel with the reproducer provided in commit
9d8cebd, we get the correct result:
addr = 0x7ffa5aaa2000
[snip]
7ffa5aaa2000-
7ffa5aaa6000 rw-p
00000000 00:00 0
7fffd556f000-
7fffd5584000 rw-p
00000000 00:00 0 [stack]
Signed-off-by: Caspar Zhang <caspar@casparzhang.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct vm_area_struct *prev;
struct vm_area_struct *vma;
int err = 0;
- pgoff_t pgoff;
unsigned long vmstart;
unsigned long vmend;
vmstart = max(start, vma->vm_start);
vmend = min(end, vma->vm_end);
- pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
- vma->anon_vma, vma->vm_file, pgoff, new_pol);
+ vma->anon_vma, vma->vm_file, vma->vm_pgoff,
+ new_pol);
if (prev) {
vma = prev;
next = vma->vm_next;