| Message ID | 1604643893-8223-1-git-send-email-zhengchuan@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | migration/multifd: fix hangup with TLS-Multifd due to blocking handshake | expand |
On Fri, Nov 06, 2020 at 02:24:53PM +0800, Chuan Zheng wrote: > The qemu main loop could hang up forever when we enable TLS+Multifd. > The Src multifd_send_0 invokes tls handshake, it sends hello to sever > and wait response. > However, the Dst main qemu loop has been waiting recvmsg() for multifd_recv_1. > Both of Src and Dst main qemu loop are blocking and waiting for reponse which > results in hanging up forever. > > Src: (multifd_send_0) Dst: (multifd_recv_1) > multifd_channel_connect migration_channel_process_incoming > multifd_tls_channel_connect migration_tls_channel_process_incoming > multifd_tls_channel_connect qio_channel_tls_handshake_task > qio_channel_tls_handshake gnutls_handshake > qio_channel_tls_handshake_task ... > qcrypto_tls_session_handshake ... > gnutls_handshake ... > ... ... > recvmsg (Blocking I/O waiting for response) recvmsg (Blocking I/O waiting for response) > > Fix this by offloadinig handshake work to a background thread. > > Reported-by: Yan Jin <jinyan12@huawei.com> > Suggested-by: Daniel P. Berrangé <berrange@redhat.com> > Signed-off-by: Chuan Zheng <zhengchuan@huawei.com> > --- > migration/multifd.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Regards, Daniel
* Chuan Zheng (zhengchuan@huawei.com) wrote: > The qemu main loop could hang up forever when we enable TLS+Multifd. > The Src multifd_send_0 invokes tls handshake, it sends hello to sever > and wait response. > However, the Dst main qemu loop has been waiting recvmsg() for multifd_recv_1. > Both of Src and Dst main qemu loop are blocking and waiting for reponse which > results in hanging up forever. > > Src: (multifd_send_0) Dst: (multifd_recv_1) > multifd_channel_connect migration_channel_process_incoming > multifd_tls_channel_connect migration_tls_channel_process_incoming > multifd_tls_channel_connect qio_channel_tls_handshake_task > qio_channel_tls_handshake gnutls_handshake > qio_channel_tls_handshake_task ... > qcrypto_tls_session_handshake ... > gnutls_handshake ... > ... ... > recvmsg (Blocking I/O waiting for response) recvmsg (Blocking I/O waiting for response) > > Fix this by offloadinig handshake work to a background thread. > > Reported-by: Yan Jin <jinyan12@huawei.com> > Suggested-by: Daniel P. Berrangé <berrange@redhat.com> > Signed-off-by: Chuan Zheng <zhengchuan@huawei.com> Queued > --- > migration/multifd.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) > > diff --git a/migration/multifd.c b/migration/multifd.c > index 68b171f..88486b9 100644 > --- a/migration/multifd.c > +++ b/migration/multifd.c > @@ -739,6 +739,19 @@ static void multifd_tls_outgoing_handshake(QIOTask *task, > multifd_channel_connect(p, ioc, err); > } > > +static void *multifd_tls_handshake_thread(void *opaque) > +{ > + MultiFDSendParams *p = opaque; > + QIOChannelTLS *tioc = QIO_CHANNEL_TLS(p->c); > + > + qio_channel_tls_handshake(tioc, > + multifd_tls_outgoing_handshake, > + p, > + NULL, > + NULL); > + return NULL; > +} > + > static void multifd_tls_channel_connect(MultiFDSendParams *p, > QIOChannel *ioc, > Error **errp) > @@ -754,12 +767,10 @@ static void multifd_tls_channel_connect(MultiFDSendParams *p, > > trace_multifd_tls_outgoing_handshake_start(ioc, tioc, hostname); > qio_channel_set_name(QIO_CHANNEL(tioc), "multifd-tls-outgoing"); > - qio_channel_tls_handshake(tioc, > - multifd_tls_outgoing_handshake, > - p, > - NULL, > - NULL); > - > + p->c = QIO_CHANNEL(tioc); > + qemu_thread_create(&p->thread, "multifd-tls-handshake-worker", > + multifd_tls_handshake_thread, p, > + QEMU_THREAD_JOINABLE); > } > > static bool multifd_channel_connect(MultiFDSendParams *p, > -- > 1.8.3.1 > >
diff --git a/migration/multifd.c b/migration/multifd.c index 68b171f..88486b9 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -739,6 +739,19 @@ static void multifd_tls_outgoing_handshake(QIOTask *task, multifd_channel_connect(p, ioc, err); } +static void *multifd_tls_handshake_thread(void *opaque) +{ + MultiFDSendParams *p = opaque; + QIOChannelTLS *tioc = QIO_CHANNEL_TLS(p->c); + + qio_channel_tls_handshake(tioc, + multifd_tls_outgoing_handshake, + p, + NULL, + NULL); + return NULL; +} + static void multifd_tls_channel_connect(MultiFDSendParams *p, QIOChannel *ioc, Error **errp) @@ -754,12 +767,10 @@ static void multifd_tls_channel_connect(MultiFDSendParams *p, trace_multifd_tls_outgoing_handshake_start(ioc, tioc, hostname); qio_channel_set_name(QIO_CHANNEL(tioc), "multifd-tls-outgoing"); - qio_channel_tls_handshake(tioc, - multifd_tls_outgoing_handshake, - p, - NULL, - NULL); - + p->c = QIO_CHANNEL(tioc); + qemu_thread_create(&p->thread, "multifd-tls-handshake-worker", + multifd_tls_handshake_thread, p, + QEMU_THREAD_JOINABLE); } static bool multifd_channel_connect(MultiFDSendParams *p,
The qemu main loop could hang up forever when we enable TLS+Multifd. The Src multifd_send_0 invokes tls handshake, it sends hello to sever and wait response. However, the Dst main qemu loop has been waiting recvmsg() for multifd_recv_1. Both of Src and Dst main qemu loop are blocking and waiting for reponse which results in hanging up forever. Src: (multifd_send_0) Dst: (multifd_recv_1) multifd_channel_connect migration_channel_process_incoming multifd_tls_channel_connect migration_tls_channel_process_incoming multifd_tls_channel_connect qio_channel_tls_handshake_task qio_channel_tls_handshake gnutls_handshake qio_channel_tls_handshake_task ... qcrypto_tls_session_handshake ... gnutls_handshake ... ... ... recvmsg (Blocking I/O waiting for response) recvmsg (Blocking I/O waiting for response) Fix this by offloadinig handshake work to a background thread. Reported-by: Yan Jin <jinyan12@huawei.com> Suggested-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com> --- migration/multifd.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-)