On Tue, 1 Jun 2021 10:50:24 -0400 Peter Xu <pet...@redhat.com> wrote:
> On Tue, Jun 01, 2021 at 02:40:31AM -0300, Leonardo Bras wrote: > > After yank feature was introduced in migration, whenever migration > > is started using TLS, the following error happens in both source and > > destination hosts: > > > > (qemu) qemu-kvm: ../util/yank.c:107: yank_unregister_instance: > > Assertion `QLIST_EMPTY(&entry->yankfns)' failed. > > > > This happens because of a missing yank_unregister_function() when using > > qio-channel-tls. > > > > Fix this by also allowing TYPE_QIO_CHANNEL_TLS object type to perform > > yank_unregister_function() in channel_close() and multifd_load_cleanup(). > > > > Also, inside migration_channel_connect() and > > migration_channel_process_incoming() move yank_register_function() so > > it only runs once on a TLS migration. > > Slightly inaccurate I guess, as it was run once too before this patch, but not > paired for tls? > > IIUC when we call the 2nd time at below chunk we won't register again: > > if (object_dynamic_cast(OBJECT(ioc), TYPE_QIO_CHANNEL_SOCKET)) { > yank_register_function(MIGRATION_YANK_INSTANCE, > migration_yank_iochannel, > QIO_CHANNEL(ioc)); > } > > Because the 2nd call will be TYPE_QIO_CHANNEL_TLS, so object_dynamic_cast() > will return with a failure, I think (note, TYPE_QIO_CHANNEL_TLS's parent is > TYPE_QIO_CHANNEL, not TYPE_QIO_CHANNEL_SOCKET). > > > > > Fixes: b5eea99ec2f ("migration: Add yank feature", 2021-01-13) > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1964326 > > Signed-off-by: Leonardo Bras <leobra...@gmail.com> > > Reviewed-by: Peter Xu <pet...@redhat.com> > > Thanks Leo! > > I have one pure question not directly related to Leo's patch (probably for > Lukas?): we check OBJECT(ioc)->ref == 1 when unregister each function. In > what > case will the ref be not one? > If a return path is opened with qemu_file_get_return_path(), it will take additional references: qemu_file_get_return_path() (qemu-file.c) f->ops->get_return_path() -> channel_get_input_return_path() (qemu-file-channel.c) qemu_fopen_channel_input() (qemu-file-channel.c) object_ref(OBJECT(ioc)) Regards, Lukas Straub --
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