From: Björn Töpel bjorn.topel@intel.com
[ Upstream commit 9764f4b301c3e7eb3b75eec85b73cad449cdbb0d ]
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 jonathan.lemon@gmail.com Fixes: 423f38329d26 ("xsk: add umem fill queue support and mmap") Signed-off-by: Björn Töpel bjorn.topel@intel.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/xdp/xsk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index b580078f04d1..72caa4fb13f4 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -454,7 +454,7 @@ 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; @@ -534,7 +534,7 @@ 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; }