I think I know what's happening here. Test 153 has a number of actions that must be executed sequentially in an specific order. But some of those actions are driven using "_send_qemu_cmd()" without specifying an expected return value. The absence of this return value, means this function writes to QMP without waiting for an answer. This means that, while unlikely, the next action can be executed while the first one didn't have yet an effect. I suppose this behavior can be exacerbated on machines with limited resources or highly loaded. I'll produce a patch to discuss this possibility upstream. Thanks, Sergio.
Upstream has a patch addressing this issue, included in qemu-4.0: https://lists.nongnu.org/archive/html/qemu-devel/2019-03/msg05181.html
Hi Karen, Could you please help verify this bug ? Thanks.
Created attachment 1579463 [details] Log file verification that iotest 153 now passes on rhel-av-8.1.0/master-4.0.0 branch
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2019:3723