Re: [syzbot] [ceph?] kernel BUG in __open_session

[Edward Adam Davis]

From: Edward Aadm Davis <eadavis@xxxxxxxx>

#syz test: upstream 50d05c7c76c9

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 72935f665f11..0f20d6c5e4bd 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -818,7 +818,11 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 					struct ceph_options *opt)
 {
 	struct ceph_fs_client *fsc;
-	int err;
+	int err, num_mon;
+
+	num_mon = opt->num_mon;
+	if (num_mon == 0 || num_mon > CEPH_MAX_MON)
+		return ERR_PTR(-EINVAL);
 
 	fsc = kzalloc_obj(*fsc);
 	if (!fsc) {