Re: [Qemu-devel] [PATCH] linux-aio: avoid deadlock in nested aio_poll() calls

[Marcin Gibuła]

W dniu 2014-08-04 17:56, Stefan Hajnoczi pisze:
> If two Linux AIO request completions are fetched in the same
> io_getevents() call, QEMU will deadlock if request A's callback waits
> for request B to complete using an aio_poll() loop.  This was reported
> to happen with the mirror blockjob.

s/mirror/commit/

> This patch moves completion processing into a BH and makes it resumable.
> Nested event loops can resume completion processing so that request B
> will complete and the deadlock will not occur.
>
> Cc: Kevin Wolf <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Cc: Ming Lei <address@hidden>
> Cc: Marcin Gibuła <address@hidden>
> Reported-by: Marcin Gibuła <address@hidden>
> Signed-off-by: Stefan Hajnoczi <address@hidden>

I'll test it tomorrow.

--
mg