[v1.18.x] prov/ucx: Fix segfault in ucx_send_callback

In one code path, the request was not initialized before the callback
function is called. As a result, NULL cq was dereferenced, leading to
segfault.

Signed-off-by: Jianxin Xiong <[email protected]>
(cherry picked from commit 409c00d)

prov/ucx/src/ucx_core.c

@@ -94,6 +94,25 @@ ssize_t ucx_do_sendmsg(struct fid_ep *ep, const struct fi_msg_tagged *msg,
 		return ucx_translate_errcode(*(ucs_status_t*)status);
 	}
 
+	if (UCS_PTR_STATUS(status) != UCS_OK) {
+		struct ucx_request *req = (struct ucx_request *)status;
+
+		/*
+		 * Set up the req fields before the callback function is called
+		 * (in ucp_worker_progress or ucp_worker_flush).
+		 */
+		req->ep = u_ep;
+		if (!no_completion) {
+			req->completion.op_context = msg->context;
+			req->completion.flags = FI_SEND |
+						(mode == UCX_MSG ? FI_MSG : FI_TAGGED);
+			req->completion.len = msg->msg_iov[0].iov_len;
+			req->completion.buf = msg->msg_iov[0].iov_base;
+			req->completion.tag = msg->tag;
+			req->cq = cq;
+		}
+	}
+
 	if (flags & FI_INJECT) {
 		if(UCS_PTR_STATUS(status) != UCS_OK) {
 			while ((cstatus = ucp_request_check_status(status))
@@ -110,13 +129,6 @@ ssize_t ucx_do_sendmsg(struct fid_ep *ep, const struct fi_msg_tagged *msg,
 		goto done;
 	}
 
-	if (no_completion) {
-		if (UCS_PTR_STATUS(status) != UCS_OK)
-			goto fence;
-
-		goto done;
-	}
-
 	if (msg->context) {
 		struct fi_context *ctx = ((struct fi_context*)(msg->context));
 
@@ -129,16 +141,6 @@ ssize_t ucx_do_sendmsg(struct fid_ep *ep, const struct fi_msg_tagged *msg,
 		 * Not done yet. completion will be handled by the callback
 		 * function.
 		 */
-		struct ucx_request *req = (struct ucx_request *)status;
-
-		req->completion.op_context = msg->context;
-		req->completion.flags = FI_SEND |
-					(mode == UCX_MSG ? FI_MSG : FI_TAGGED);
-		req->completion.len = msg->msg_iov[0].iov_len;
-		req->completion.buf = msg->msg_iov[0].iov_base;
-		req->completion.tag = msg->tag;
-		req->ep = u_ep;
-		req->cq = cq;
 		goto fence;
 	}