From: Ilya Maximets <i.maximets@samsung.com>
Date: Fri, 7 Jun 2019 20:27:32 +0300
Subject: xdp: check device pointer before clearing
Patch-mainline: v5.2-rc6
Git-commit: 01d76b5317003e019ace561a9b775f51aafdfdc4
References: bsc#1109837

We should not call 'ndo_bpf()' or 'dev_put()' with NULL argument.

Fixes: c9b47cc1fabc ("xsk: fix bug when trying to use both copy and zero-copy on one queue id")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/xdp/xdp_umem.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -140,6 +140,9 @@ static void xdp_umem_clear_dev(struct xd
 	struct netdev_bpf bpf;
 	int err;
 
+	if (!umem->dev)
+		return;
+
 	if (umem->zc) {
 		bpf.command = XDP_SETUP_XSK_UMEM;
 		bpf.xsk.umem = NULL;
@@ -153,11 +156,9 @@ static void xdp_umem_clear_dev(struct xd
 			WARN(1, "failed to disable umem!\n");
 	}
 
-	if (umem->dev) {
-		rtnl_lock();
-		xdp_clear_umem_at_qid(umem->dev, umem->queue_id);
-		rtnl_unlock();
-	}
+	rtnl_lock();
+	xdp_clear_umem_at_qid(umem->dev, umem->queue_id);
+	rtnl_unlock();
 
 	if (umem->zc) {
 		dev_put(umem->dev);