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  1. Nov 18, 2016
    • Dave Airlie's avatar
      Revert "drm/mediatek: fix a typo of OD_CFG to OD_RELAYMODE" · e9f01049
      Dave Airlie authored 
      This reverts commit 83ba62bc

.

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      e9f01049
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.dk/linux-block · 62389867
      Linus Torvalds authored 
      Pull block fixes from Jens Axboe:
 "A set of fixes, one for NVMe from Keith, and a set for nvme-{rdma,t,f}
  from the usual suspects, fixing actual problems that would be a shame
  to release 4.9 with"

* 'for-linus' of git://git.kernel.dk/linux-block:
  nvme/pci: Don't free queues on error
  nvmet-rdma: drain the queue-pair just before freeing it
  nvme-rdma: stop and free io queues on connect failure
  nvmet-rdma: don't forget to delete a queue from the list of connection failed
  nvmet: Don't queue fatal error work if csts.cfs is set
  nvme-rdma: reject non-connect commands before the queue is live
  nvmet-rdma: Fix possible NULL deref when handling rdma cm events
      62389867
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma · 57400d30
      Linus Torvalds authored 
      Pull rmda fixes from Doug Ledford.
 "First round of -rc fixes.

  Due to various issues, I've been away and couldn't send a pull request
  for about three weeks. There were a number of -rc patches that built
  up in the meantime (some where there already from the early -rc
  stages). Obviously, there were way too many to send now, so I tried to
  pare the list down to the more important patches for the -rc cycle.

  Most of the code has had plenty of soak time at the various vendor's
  testing setups, so I doubt there will be another -rc pull request this
  cycle. I also tried to limit the patches to those with smaller
  footprints, so even though a shortlog is longer than I would like, the
  actual diffstat is mostly very small with the exception of just three
  files that had more changes, and a couple files with pure removals.

  Summary:
   - Misc Intel hfi1 fixes
   - Misc Mellanox mlx4, mlx5, and rxe fixes
   - A couple cxgb4 fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (34 commits)
  iw_cxgb4: invalidate the mr when posting a read_w_inv wr
  iw_cxgb4: set *bad_wr for post_send/post_recv errors
  IB/rxe: Update qp state for user query
  IB/rxe: Clear queue buffer when modifying QP to reset
  IB/rxe: Fix handling of erroneous WR
  IB/rxe: Fix kernel panic in UDP tunnel with GRO and RX checksum
  IB/mlx4: Fix create CQ error flow
  IB/mlx4: Check gid_index return value
  IB/mlx5: Fix NULL pointer dereference on debug print
  IB/mlx5: Fix fatal error dispatching
  IB/mlx5: Resolve soft lock on massive reg MRs
  IB/mlx5: Use cache line size to select CQE stride
  IB/mlx5: Validate requested RQT size
  IB/mlx5: Fix memory leak in query device
  IB/core: Avoid unsigned int overflow in sg_alloc_table
  IB/core: Add missing check for addr_resolve callback return value
  IB/core: Set routable RoCE gid type for ipv4/ipv6 networks
  IB/cm: Mark stale CM id's whenever the mad agent was unregistered
  IB/uverbs: Fix leak of XRC target QPs
  IB/hfi1: Remove incorrect IS_ERR check
  ...
      57400d30
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · bec1b089
      Linus Torvalds authored 
      Pull vfs fixes from Al Viro:
 "A couple of regression fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix iov_iter_advance() for ITER_PIPE
  xattr: Fix setting security xattrs on sockfs
      bec1b089
    • Linus Torvalds's avatar
      Merge tag 'for-linus-4.9-rc5-ofs-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux · d46bc34d
      Linus Torvalds authored 
      Pull orangefs fix from Mike Marshall:
 "orangefs: add .owner to debugfs file_operations

  Without ".owner = THIS_MODULE" it is possible to crash the kernel by
  unloading the Orangefs module while someone is reading debugfs files"

* tag 'for-linus-4.9-rc5-ofs-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux:
  orangefs: add .owner to debugfs file_operations
      d46bc34d
    • Aaron Lu's avatar
      mremap: fix race between mremap() and page cleanning · 5d190420
      Aaron Lu authored 
      Prior to 3.15, there was a race between zap_pte_range() and
page_mkclean() where writes to a page could be lost.  Dave Hansen
discovered by inspection that there is a similar race between
move_ptes() and page_mkclean().

We've been able to reproduce the issue by enlarging the race window with
a msleep(), but have not been able to hit it without modifying the code.
So, we think it's a real issue, but is difficult or impossible to hit in
practice.

The zap_pte_range() issue is fixed by commit 1cf35d47

("mm: split
'tlb_flush_mmu()' into tlb flushing and memory freeing parts").  And
this patch is to fix the race between page_mkclean() and mremap().

Here is one possible way to hit the race: suppose a process mmapped a
file with READ | WRITE and SHARED, it has two threads and they are bound
to 2 different CPUs, e.g.  CPU1 and CPU2.  mmap returned X, then thread
1 did a write to addr X so that CPU1 now has a writable TLB for addr X
on it.  Thread 2 starts mremaping from addr X to Y while thread 1
cleaned the page and then did another write to the old addr X again.
The 2nd write from thread 1 could succeed but the value will get lost.

        thread 1                           thread 2
     (bound to CPU1)                    (bound to CPU2)

  1: write 1 to addr X to get a
     writeable TLB on this CPU

                                        2: mremap starts

                                        3: move_ptes emptied PTE for addr X
                                           and setup new PTE for addr Y and
                                           then dropped PTL for X and Y

  4: page laundering for N by doing
     fadvise FADV_DONTNEED. When done,
     pageframe N is deemed clean.

  5: *write 2 to addr X

                                        6: tlb flush for addr X

  7: munmap (Y, pagesize) to make the
     page unmapped

  8: fadvise with FADV_DONTNEED again
     to kick the page off the pagecache

  9: pread the page from file to verify
     the value. If 1 is there, it means
     we have lost the written 2.

  *the write may or may not cause segmentation fault, it depends on
  if the TLB is still on the CPU.

Please note that this is only one specific way of how the race could
occur, it didn't mean that the race could only occur in exact the above
config, e.g. more than 2 threads could be involved and fadvise() could
be done in another thread, etc.

For anonymous pages, they could race between mremap() and page reclaim:
THP: a huge PMD is moved by mremap to a new huge PMD, then the new huge
PMD gets unmapped/splitted/pagedout before the flush tlb happened for
the old huge PMD in move_page_tables() and we could still write data to
it.  The normal anonymous page has similar situation.

To fix this, check for any dirty PTE in move_ptes()/move_huge_pmd() and
if any, did the flush before dropping the PTL.  If we did the flush for
every move_ptes()/move_huge_pmd() call then we do not need to do the
flush in move_pages_tables() for the whole range.  But if we didn't, we
still need to do the whole range flush.

Alternatively, we can track which part of the range is flushed in
move_ptes()/move_huge_pmd() and which didn't to avoid flushing the whole
range in move_page_tables().  But that would require multiple tlb
flushes for the different sub-ranges and should be less efficient than
the single whole range flush.

KBuild test on my Sandybridge desktop doesn't show any noticeable change.
v4.9-rc4:
  real    5m14.048s
  user    32m19.800s
  sys     4m50.320s

With this commit:
  real    5m13.888s
  user    32m19.330s
  sys     4m51.200s

Reported-by: default avatarDave Hansen <dave.hansen@intel.com>
Signed-off-by: default avatarAaron Lu <aaron.lu@intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5d190420
  3. Nov 17, 2016
  5. Nov 16, 2016