On 10/26/20 7:25 AM, Jason Gunthorpe wrote:
There are two flows for handling RDMA_CM_EVENT_ROUTE_RESOLVED, either the
handler triggers a completion and another thread does rdma_connect() or
the handler directly calls rdma_connect().
In all cases rdma_connect() needs to hold the handler_mutex, but when
handler's are invoked this is already held by the core code. This causes
ULPs using the 2nd method to deadlock.
Provide a rdma_connect_locked() and have all ULPs call it from their
handlers.
Reported-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
Fixes: 2a7cec538169 ("RDMA/cma: Fix locking for the RDMA_CM_CONNECT state"
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
[....]
diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index 06603dd1c8aa38..b36b60668b1da9 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -956,9 +956,10 @@ int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id, bool isv6)
rds_ib_cm_fill_conn_param(conn, &conn_param, &dp,
conn->c_proposed_version,
UINT_MAX, UINT_MAX, isv6);
- ret = rdma_connect(cm_id, &conn_param);
+ ret = rdma_connect_locked(cm_id, &conn_param);
if (ret)
- rds_ib_conn_error(conn, "rdma_connect failed (%d)\n", ret);
+ rds_ib_conn_error(conn, "rdma_connect_locked failed (%d)\n",
+ ret);
out:
/* Beware - returning non-zero tells the rdma_cm to destroy
For RDS part,
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
