xdp: check device pointer before clearing

[ Upstream commit 01d76b5317003e019ace561a9b775f51aafdfdc4 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 989e52386c358a34a566660933002827ba165068..2f7e2c33a81205d54f481f50068dd657546d412c 100644 (file)
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -143,6 +143,9 @@ static void xdp_umem_clear_dev(struct xdp_umem *umem)
        struct netdev_bpf bpf;
        int err;
 
+       if (!umem->dev)
+               return;
+
        if (umem->zc) {
                bpf.command = XDP_SETUP_XSK_UMEM;
                bpf.xsk.umem = NULL;
@@ -156,11 +159,9 @@ static void xdp_umem_clear_dev(struct xdp_umem *umem)
                        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);