diff --git a/fs/namespace.c b/fs/namespace.c
index d470a369d42b..c5ada826d488 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -5410,6 +5410,21 @@ static int grab_requested_root(struct mnt_namespace *ns, struct path *root)
 	return 0;
 }
 
+/* This must be updated whenever a new flag is added */
+#define STATMOUNT_SUPPORTED (STATMOUNT_SB_BASIC | \
+			     STATMOUNT_MNT_BASIC | \
+			     STATMOUNT_PROPAGATE_FROM | \
+			     STATMOUNT_MNT_ROOT | \
+			     STATMOUNT_MNT_POINT | \
+			     STATMOUNT_FS_TYPE | \
+			     STATMOUNT_MNT_NS_ID | \
+			     STATMOUNT_MNT_OPTS | \
+			     STATMOUNT_FS_SUBTYPE | \
+			     STATMOUNT_SB_SOURCE | \
+			     STATMOUNT_OPT_ARRAY | \
+			     STATMOUNT_OPT_SEC_ARRAY | \
+			     STATMOUNT_SUPPORTED_MASK)
+
 static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
 			struct mnt_namespace *ns)
 {
@@ -5479,9 +5494,17 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
 	if (!err && s->mask & STATMOUNT_MNT_NS_ID)
 		statmount_mnt_ns_id(s, ns);
 
+	if (!err && s->mask & STATMOUNT_SUPPORTED_MASK) {
+		s->sm.mask |= STATMOUNT_SUPPORTED_MASK;
+		s->sm.supported_mask = STATMOUNT_SUPPORTED;
+	}
+
 	if (err)
 		return err;
 
+	/* Are there bits in the return mask not present in STATMOUNT_SUPPORTED? */
+	WARN_ON_ONCE(~STATMOUNT_SUPPORTED & s->sm.mask);
+
 	return 0;
 }
 
diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h
index c07008816aca..c553dc4ba684 100644
--- a/include/uapi/linux/mount.h
+++ b/include/uapi/linux/mount.h
@@ -179,7 +179,8 @@ struct statmount {
 	__u32 opt_array;	/* [str] Array of nul terminated fs options */
 	__u32 opt_sec_num;	/* Number of security options */
 	__u32 opt_sec_array;	/* [str] Array of nul terminated security options */
-	__u64 __spare2[46];
+	__u64 supported_mask;	/* Mask flags that this kernel supports */
+	__u64 __spare2[45];
 	char str[];		/* Variable size part containing strings */
 };
 
@@ -217,6 +218,7 @@ struct mnt_id_req {
 #define STATMOUNT_SB_SOURCE		0x00000200U	/* Want/got sb_source */
 #define STATMOUNT_OPT_ARRAY		0x00000400U	/* Want/got opt_... */
 #define STATMOUNT_OPT_SEC_ARRAY		0x00000800U	/* Want/got opt_sec... */
+#define STATMOUNT_SUPPORTED_MASK	0x00001000U	/* Want/got supported mask flags */
 
 /*
  * Special @mnt_id values that can be passed to listmount