On 04/08/2015 11:22, Peter Lieven wrote: >>>>> edec47c main-loop: fix qemu_notify_event for aio_notify optimization >>>> Part of the above AioContext series. >>> So either the whole series or none of them I guess? >> It's a separate bug, and theoretically it's there in 2.3.1 as well, but >> no one ever reproduced it (it would hang in make check) so not >> worthwhile. > > Can you give me a pointer what the symtoms where?
If a thread tries to wake up the main thread using qemu_notify_event(), the main thread will never wake up. This for example could happen if the first thread calls qemu_set_fd_handler() or timer_mod(). > I have a qemu-img convert job on x86_64 that reproducibly hangs on > bdrv_drain_all at the end of the convert process. > I convert from nfs:// to local storage here. I try to figure out which BS > reports busy. Qemu here is still 2.2.1. qemu-img does not use main-loop, so this cannot be the cause. The AioContext bugs only happen when you have a thread executing the main loop and one thread executing aio_poll, so they can also be excluded as the cause of qemu-img problems. Paolo
