From 9764f4b301c3e7eb3b75eec85b73cad449cdbb0d Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Wed, 4 Sep 2019 13:49:11 +0200 Subject: xsk: avoid store-tearing when assigning umem MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The umem member of struct xdp_sock is read outside of the control mutex, in the mmap implementation, and needs a WRITE_ONCE to avoid potential store-tearing. Acked-by: Jonathan Lemon Fixes: 423f38329d26 ("xsk: add umem fill queue support and mmap") Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/xdp') diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 271d8d3fb11e..8c9056f06989 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -644,7 +644,7 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) } xdp_get_umem(umem_xs->umem); - xs->umem = umem_xs->umem; + WRITE_ONCE(xs->umem, umem_xs->umem); sockfd_put(sock); } else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) { err = -EINVAL; @@ -751,7 +751,7 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, /* Make sure umem is ready before it can be seen by others */ smp_wmb(); - xs->umem = umem; + WRITE_ONCE(xs->umem, umem); mutex_unlock(&xs->mutex); return 0; } -- cgit v1.2.3-59-g8ed1b