Re: [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed

[Paolo Bonzini]

Il 16/09/2014 14:52, Kevin Wolf ha scritto:
> Yes, that's true. We can't fix this problem in qcow2, though, because
> it's a more general one.  I think we must make sure that
> bdrv_invalidate_cache() doesn't yield.
> 
> Either by forbidding to run bdrv_invalidate_cache() in a coroutine and
> moving the problem to the caller (where and why is it even called from a
> coroutine?), or possibly by creating a new coroutine for the driver
> callback and running that in a nested event loop that only handles
> bdrv_invalidate_cache() callbacks, so that the NBD server doesn't get a
> chance to process new requests in this thread.

Incoming migration runs in a coroutine (the coroutine entry point is
process_incoming_migration_co).  But everything after qemu_fclose() can
probably be moved into a separate bottom half, so that it gets out of
coroutine context.

Paolo