From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Fix a race where the destination might try and send the source a
WRID_READY before the source has done a post-recv for it.
rdma_post_recv has to happen after the qp exists, and we're
OK since we've already called qemu_rdma_source_init that calls
qemu_alloc_qp.
This corresponds to:
https://bugzilla.redhat.com/show_bug.cgi?id=1285044
The race can be triggered by adding a few ms wait before this
post_recv_control (which was originally due to me turning on loads of
debug).
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
migration/rdma.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/migration/rdma.c b/migration/rdma.c
index c6bc607a03..6111e10c70 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -2365,6 +2365,12 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
caps_to_network(&cap);
+ ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
+ if (ret) {
+ ERROR(errp, "posting second control recv");
+ goto err_rdma_source_connect;
+ }
+
ret = rdma_connect(rdma->cm_id, &conn_param);
if (ret) {
perror("rdma_connect");
@@ -2405,12 +2411,6 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
rdma_ack_cm_event(cm_event);
- ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
- if (ret) {
- ERROR(errp, "posting second control recv!");
- goto err_rdma_source_connect;
- }
-
rdma->control_ready_expected = 1;
rdma->nb_sent = 0;
return 0;
--
2.13.0