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| author | Chuan Zheng <zhengchuan@huawei.com> | 2020-11-06 14:24:53 +0800 |
|---|---|---|
| committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2020-11-12 14:35:29 +0000 |
| commit | a1af605bd5ade1a6dd571f553a6746b97f3d6869 (patch) | |
| tree | 120240d42ba9e7bc18b322f3599c12ffa33993df | |
| parent | 136fc6aa2cf38205fa3b47e155ebac11baccc789 (diff) | |
| download | qemu-a1af605bd5ade1a6dd571f553a6746b97f3d6869.zip qemu-a1af605bd5ade1a6dd571f553a6746b97f3d6869.tar.gz qemu-a1af605bd5ade1a6dd571f553a6746b97f3d6869.tar.bz2 | |
migration/multifd: fix hangup with TLS-Multifd due to blocking handshake
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>
Message-Id: <1604643893-8223-1-git-send-email-zhengchuan@huawei.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
| -rw-r--r-- | migration/multifd.c | 23 |
1 files 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, |