From 6c4338f2ef3b36c050a85514eb2b67f48066687b Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Wed, 4 Jan 2017 16:09:45 +0000
Subject: [PATCH] The callers of kern_getfsstat(UIO_SYSSPACE) expect that *buf
 always returns memory which must be freed, regardless of the error.  Assign
 NULL to *buf in case we are not going to allocate any memory due to invalid
 mode.

Reported and tested by:	pho
Reviewed by:	jhb
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks (together with r310638)
Differential revision:	https://reviews.freebsd.org/D9042
---
 sys/kern/vfs_syscalls.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index b51122aacc39..6407732c9548 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -429,6 +429,8 @@ kern_getfsstat(struct thread *td, struct statfs **buf, size_t bufsize,
 	case MNT_NOWAIT:
 		break;
 	default:
+		if (bufseg == UIO_SYSSPACE)
+			*buf = NULL;
 		return (EINVAL);
 	}
 restart: