[Qemu-block] [PATCH 0/3] coroutine: avoid co_queue_wakeup recursion

[Stefan Hajnoczi]

co_queue_wakeup is currently implemented in a recursive fashion.  Pathological
patterns of aio_co_enter() between coroutines can cause stack exhaustion.

This patch series implements co_queue_wakeup iteratively and avoids stack
exhaustion.

This issue was originally reported with qemu-img convert but I don't have a
good reproducer.  See Patch 3 for a test-aio test case instead.

Stefan Hajnoczi (3):
  queue: add QSIMPLEQ_PREPEND()
  coroutine: avoid co_queue_wakeup recursion
  coroutine: add test-aio coroutine queue chaining test case

 include/qemu/coroutine_int.h |   1 -
 include/qemu/queue.h         |   8 ++++
 block/io.c                   |   3 +-
 tests/test-aio.c             |  65 ++++++++++++++++++++-----
 util/qemu-coroutine-lock.c   |  34 -------------
 util/qemu-coroutine.c        | 110 +++++++++++++++++++++++--------------------
 6 files changed, 120 insertions(+), 101 deletions(-)

-- 
2.14.3