Re: [syzbot] [fs?] BUG: unable to handle kernel NULL pointer dereference in path_from_stashed

[Edward Adam Davis]

time_ns is null ?

#syz test: upstream 5e0497553643

diff --git a/fs/pidfs.c b/fs/pidfs.c
index c9cb14181def..fdae58eb1d98 100644
--- a/fs/pidfs.c
+++ b/fs/pidfs.c
@@ -168,6 +168,8 @@ static long pidfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case PIDFD_GET_TIME_NAMESPACE:
 		get_time_ns(nsp->time_ns);
 		ns_common = to_ns_common(nsp->time_ns);
+		if (!nsp->time_ns)
+			return -EINVAL;
 		break;
 	case PIDFD_GET_TIME_FOR_CHILDREN_NAMESPACE:
 		get_time_ns(nsp->time_ns_for_children);