This is a note to let you know that I've just added the patch titled
mm: do not call do_fault_around for non-linear fault
to the 3.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-do-not-call-do_fault_around-for-non-linear-fault.patch
and it can be found in the queue-3.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From c118678bc79e8241f9d3434d9324c6400d72f48a Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <[email protected]>
Date: Wed, 23 Jul 2014 14:00:08 -0700
Subject: mm: do not call do_fault_around for non-linear fault
From: Konstantin Khlebnikov <[email protected]>
commit c118678bc79e8241f9d3434d9324c6400d72f48a upstream.
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]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3515,7 +3515,7 @@ static int do_read_fault(struct mm_struc
* if page by the offset is not ready to be mapped (cold cache or
* something).
*/
- if (vma->vm_ops->map_pages) {
+ if (vma->vm_ops->map_pages && !(flags & FAULT_FLAG_NONLINEAR)) {
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
do_fault_around(vma, address, pte, pgoff, flags);
if (!pte_same(*pte, orig_pte))
Patches currently in stable-queue which might be from [email protected] are
queue-3.15/mm-do-not-call-do_fault_around-for-non-linear-fault.patch
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