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? -- Peter Xu