tests/test-bdrv-drain: Fix too late qemu_event_reset()

PATCH In review Kevin Wolf 2 participants 2 messages Oct 1, 2018

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Kevin Wolf

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2018-10-01 15:11 UTC #0 lore raw

PATCH 1/1 tests/test-bdrv-drain: Fix too late qemu_event_reset()

qemu_event_reset() must be called before the AIO request in a different iothread is submitted. Otherwise the request could be completed before we do the qemu_event_reset() and the test would hang in qemu_event_wait().

Signed-off-by Kevin Wolf <[email protected]>

---
 tests/test-bdrv-drain.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

tests/test-bdrv-drain.c +2 -2

index c9f29c8b10..ee1740ff06 100644
@@ -694,6 +694,8 @@ static void test_iothread_common(enum drain_type drain_type, int drain_thread)
     s->bh_indirection_ctx = ctx_b;
 
     aio_ret = -EINPROGRESS;
+    qemu_event_reset(&done_event);
+
     if (drain_thread == 0) {
         acb = blk_aio_preadv(blk, 0, &qiov, 0, test_iothread_aio_cb, &aio_ret);
     } else {

@@ -723,7 +725,6 @@ static void test_iothread_common(enum drain_type drain_type, int drain_thread)
          * but the drain in this thread can continue immediately after
          * bdrv_dec_in_flight() and aio_ret might be assigned only slightly
          * later. */
-        qemu_event_reset(&done_event);
         do_drain_begin(drain_type, bs);
         g_assert_cmpint(bs->in_flight, ==, 0);

@@ -743,7 +744,6 @@ static void test_iothread_common(enum drain_type drain_type, int drain_thread)
         }
         break;
     case 1:
-        qemu_event_reset(&done_event);
         aio_bh_schedule_oneshot(ctx_a, test_iothread_drain_entry, &data);
         qemu_event_wait(&done_event);
         break;

Signature · 1 line

2.13.6

Max Reitz

Reviewed-by Tested-by on v1 1/1

2018-10-01 16:13 UTC #1 lore raw

Quoted 9 lines · Kevin Wolf

qemu_event_reset() must be called before the AIO request in a different iothread is submitted. Otherwise the request could be completed before we do the qemu_event_reset() and the test would hang in qemu_event_wait().
Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by Max Reitz <[email protected]>

Tested-by Max Reitz <[email protected]>

(I still got the same hang as the one you just reported, though -- but it happens just very rarely, so it's definitely better.)