zfs/module
Brian Behlendorf a76f3d0437
Fix deadlock in IO pipeline
In vdev_queue_aggregate() the zio_execute() bypass should not be
called under the vdev queue lock.  This can result in a deadlock
as shown in the stack traces below.

Drop the vdev queue lock then walk the parents of the aggregate IO
to determine the list of component IOs to be bypassed.  This can
be done safely without holding the io_lock since the new aggregate
IO has not yet been returned and its parents cannot change.

---  THREAD 1 ---
arc_read()
  zio_nowait()
    zio_vdev_io_start()
      vdev_queue_io() <--- mutex_enter(vq->vq_lock)
        vdev_queue_io_to_issue()
          vdev_queue_aggregate()
            zio_execute()
              zio_vdev_io_assess()
                zio_wait_for_children() <- mutex_enter(zio->io_lock)

--- THREAD 2 --- (inverse order)
arc_read()
  zio_change_priority() <- mutex_enter(zio->zio_lock)
    vdev_queue_change_io_priority() <- mutex_enter(vq->vq_lock)

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7307
2018-03-16 16:46:06 -07:00
..
avl Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
icp Change movaps to movups in AES-NI code 2018-01-31 15:17:56 -08:00
lua OpenZFS 9035 - zfs: this statement may fall through 2018-02-21 14:55:34 -08:00
nvpair Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
unicode Support -fsanitize=address with --enable-asan 2018-01-10 10:49:27 -08:00
zcommon Project Quota on ZFS 2018-02-13 14:54:54 -08:00
zfs Fix deadlock in IO pipeline 2018-03-16 16:46:06 -07:00
.gitignore Improve gitignore 2017-05-25 10:14:13 -07:00
Makefile.in OpenZFS 7431 - ZFS Channel Programs 2018-02-08 15:28:18 -08:00