treewide: add missing error handling

Change-Id: I55ccf3ff490b58f6af93e665c668428acddc8d65
Reviewed-on: https://review.monogon.dev/c/monogon/+/3019
Vouch-Run-CI: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/cloud/agent/e2e/main_test.go b/cloud/agent/e2e/main_test.go
index 02600fb..3a27803 100644
--- a/cloud/agent/e2e/main_test.go
+++ b/cloud/agent/e2e/main_test.go
@@ -122,6 +122,9 @@
 		BasicConstraintsValid: true,
 	}
 	serverCert, err := x509.CreateCertificate(rand.Reader, &serverCertTmpl, caCert, serverPubKey, caPrivKey)
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	s := grpc.NewServer(grpc.Creds(credentials.NewServerTLSFromCert(&tls.Certificate{
 		Certificate: [][]byte{serverCert},
@@ -147,10 +150,14 @@
 	if err != nil {
 		t.Fatal(err)
 	}
+
 	blobListenAddr := blobLis.Addr().(*net.TCPAddr)
 	go http.Serve(blobLis, m)
 
 	_, privateKey, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	init := apb.AgentInit{
 		TakeoverInit: &apb.TakeoverInit{
diff --git a/cloud/agent/takeover/takeover.go b/cloud/agent/takeover/takeover.go
index a62dc8c..094c688 100644
--- a/cloud/agent/takeover/takeover.go
+++ b/cloud/agent/takeover/takeover.go
@@ -165,6 +165,9 @@
 		agentParams = append(agentParams, bootparam.Param{Param: "console", Value: "ttyS0,115200"})
 	}
 	agentCmdline, err := bootparam.Marshal(agentParams, "")
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal agent params: %w", err)
+	}
 	// Stage agent payload into kernel memory
 	if err := kexec.FileLoad(kernelFile, initramfsFile, agentCmdline); err != nil {
 		return nil, fmt.Errorf("failed to load kexec payload: %w", err)
diff --git a/cloud/bmaas/bmdb/migrations_test.go b/cloud/bmaas/bmdb/migrations_test.go
index 65eef7f..1a70655 100644
--- a/cloud/bmaas/bmdb/migrations_test.go
+++ b/cloud/bmaas/bmdb/migrations_test.go
@@ -135,6 +135,9 @@
 	rows, err := conn.db.Query(`
 		SELECT machine_id, process, until, cause FROM work_backoff
 	`)
+	if err != nil {
+		t.Fatalf("Could not fetch old-style backoff data: %v", err)
+	}
 	for rows.Next() {
 		var mid, process, until, cause string
 		if err := rows.Scan(&mid, &process, &until, &cause); err != nil {
diff --git a/cloud/shepherd/provider/equinix/updater_test.go b/cloud/shepherd/provider/equinix/updater_test.go
index 9b23295..e400690 100644
--- a/cloud/shepherd/provider/equinix/updater_test.go
+++ b/cloud/shepherd/provider/equinix/updater_test.go
@@ -102,6 +102,9 @@
 			AgentPublicKey: []byte("fakefakefakefake"),
 		})
 	})
+	if err != nil {
+		t.Fatalf("failed to execute bmdb transaction: %v", err)
+	}
 
 	deadline := time.Now().Add(time.Second * 10)
 	for {