diff options
| author | Konstantin Khlebnikov <[email protected]> | 2014-07-23 14:00:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2014-07-23 15:10:54 -0700 |
| commit | c118678bc79e8241f9d3434d9324c6400d72f48a (patch) | |
| tree | 211d140913df6b88299ae8b24df2f5209a8c7e66 | |
| parent | b1923b55af43a6febb976084bf30d1a4797c92c9 (diff) | |
mm: do not call do_fault_around for non-linear fault
Ingo Korb reported that "repeated mapping of the same file on tmpfs
using remap_file_pages sometimes triggers a BUG at mm/filemap.c:202 when
the process exits".
He bisected the bug to d7c1755179b8 ("mm: implement ->map_pages for
shmem/tmpfs"), although the bug was actually added by commit
8c6e50b0290c ("mm: introduce vm_ops->map_pages()").
The problem is caused by calling do_fault_around for a _non-linear_
fault. In this case pgoff is shifted and might become negative during
calculation.
Faulting around non-linear page-fault makes no sense and breaks the
logic in do_fault_around because pgoff is shifted.
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Reported-by: Ingo Korb <[email protected]>
Tested-by: Ingo Korb <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Ning Qu <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: <[email protected]> [3.15.x]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | mm/memory.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index d67fd9fcf1f2..7e8d8205b610 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2882,7 +2882,8 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma, * if page by the offset is not ready to be mapped (cold cache or * something). */ - if (vma->vm_ops->map_pages && fault_around_pages() > 1) { + if (vma->vm_ops->map_pages && !(flags & FAULT_FLAG_NONLINEAR) && + fault_around_pages() > 1) { pte = pte_offset_map_lock(mm, pmd, address, &ptl); do_fault_around(vma, address, pte, pgoff, flags); if (!pte_same(*pte, orig_pte)) |