fix: set request page size in ListUsers rpc handler

lib/auth/users/usersv1/service.go

@@ -551,6 +551,11 @@ func (s *Service) ListUsers(ctx context.Context, req *userspb.ListUsersRequest)
 		return nil, trace.Wrap(err)
 	}
 
+	// Adjust page size, so it can't be too large.
+	if req.PageSize <= 0 || req.PageSize > apidefaults.DefaultChunkSize {
+		req.PageSize = apidefaults.DefaultChunkSize
+	}
+
 	if req.WithSecrets {
 		// TODO(fspmarshall): replace admin requirement with VerbReadWithSecrets once we've
 		// migrated to that model.

lib/cache/users.go

@@ -77,6 +77,9 @@ func (c *Cache) GetUser(ctx context.Context, name string, withSecrets bool) (typ
 
 	u, err := c.collections.users.store.get("name", name)
 	if err != nil {
+		// release read lock early
+		rg.Release()
+
 		// fallback is sane because method is never used
 		// in construction of derivative caches.
 		if trace.IsNotFound(err) {

lib/services/local/users.go

@@ -43,7 +43,6 @@ import (
 
 	"github.com/gravitational/teleport"
 	"github.com/gravitational/teleport/api/constants"
-	apidefaults "github.com/gravitational/teleport/api/defaults"
 	userspb "github.com/gravitational/teleport/api/gen/proto/go/teleport/users/v1"
 	"github.com/gravitational/teleport/api/internalutils/stream"
 	"github.com/gravitational/teleport/api/types"
@@ -115,11 +114,6 @@ func (s *IdentityService) ListUsers(ctx context.Context, req *userspb.ListUsersR
 	rangeEnd := backend.RangeEnd(backend.ExactKey(webPrefix, usersPrefix))
 	pageSize := req.PageSize
 
-	// Adjust page size, so it can't be too large.
-	if pageSize <= 0 || pageSize > apidefaults.DefaultChunkSize {
-		pageSize = apidefaults.DefaultChunkSize
-	}
-
 	// Artificially inflate the limit to account for user secrets
 	// which have the same prefix.
 	limit := int(pageSize) * 4