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
