diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2015-02-11 15:28:06 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-11 17:06:06 -0800 |
| commit | 48684a65b4e3ff544d62532c1b78962c9677b632 (patch) | |
| tree | 884da0dc303b41042c9928b40ef7ae651d34e22d /mm/mempolicy.c | |
| parent | 6f4576e3687b1f93145b89fce49d6a8fec9e7dc2 (diff) | |
mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP)
walk_page_range() silently skips vma having VM_PFNMAP set, which leads to
undesirable behaviour at client end (who called walk_page_range). For
example for pagemap_read(), when no callbacks are called against VM_PFNMAP
vma, pagemap_read() may prepare pagemap data for next virtual address
range at wrong index. That could confuse and/or break userspace
applications.
This patch avoid this misbehavior caused by vma(VM_PFNMAP) like follows:
- for pagemap_read() which has its own ->pte_hole(), call the ->pte_hole()
over vma(VM_PFNMAP),
- for clear_refs and queue_pages which have their own ->tests_walk,
just return 1 and skip vma(VM_PFNMAP). This is no problem because
these are not interested in hole regions,
- for other callers, just skip the vma(VM_PFNMAP) as a default behavior.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index b1dcd11d867a..f1bd23803576 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -591,6 +591,9 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, unsigned long endvma = vma->vm_end; unsigned long flags = qp->flags; + if (vma->vm_flags & VM_PFNMAP) + return 1; + if (endvma > end) endvma = end; if (vma->vm_start > start) |