diff options
| author | Yigal Korman <[email protected]> | 2015-11-16 14:09:15 +0200 |
|---|---|---|
| committer | Dan Williams <[email protected]> | 2015-11-18 16:54:36 -0800 |
| commit | 0df9d41ab5d43dc5b20abc8b22a6b6d098b03994 (patch) | |
| tree | 3c0c6a9a65867eeca00eab356dde7c1fbfcd2556 | |
| parent | ee82c9ed41e896bd47e121d87e4628de0f2656a3 (diff) | |
mm, dax: fix DAX deadlocks (COW fault)
DAX handling of COW faults has wrong locking sequence:
dax_fault does i_mmap_lock_read
do_cow_fault does i_mmap_unlock_write
Ross's commit[1] missed a fix[2] that Kirill added to Matthew's
commit[3].
Original COW locking logic was introduced by Matthew here[4].
This should be applied to v4.3 as well.
[1] 0f90cc6609c7 mm, dax: fix DAX deadlocks
[2] 52a2b53ffde6 mm, dax: use i_mmap_unlock_write() in do_cow_fault()
[3] 843172978bb9 dax: fix race between simultaneous faults
[4] 2e4cdab0584f mm: allow page fault handlers to perform the COW
Cc: <[email protected]>
Cc: Boaz Harrosh <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Acked-by: Ross Zwisler <[email protected]>
Signed-off-by: Yigal Korman <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
| -rw-r--r-- | mm/memory.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/memory.c b/mm/memory.c index deb679c31f2a..c387430f06c3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3015,9 +3015,9 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma, } else { /* * The fault handler has no page to lock, so it holds - * i_mmap_lock for write to protect against truncate. + * i_mmap_lock for read to protect against truncate. */ - i_mmap_unlock_write(vma->vm_file->f_mapping); + i_mmap_unlock_read(vma->vm_file->f_mapping); } goto uncharge_out; } @@ -3031,9 +3031,9 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma, } else { /* * The fault handler has no page to lock, so it holds - * i_mmap_lock for write to protect against truncate. + * i_mmap_lock for read to protect against truncate. */ - i_mmap_unlock_write(vma->vm_file->f_mapping); + i_mmap_unlock_read(vma->vm_file->f_mapping); } return ret; uncharge_out: |